vLLM v0.25.1

Highlights

This release features 2 commits from 2 contributors (1 new)!

v0.25.1 is a patch release containing two targeted bug fixes on top of v0.25.0.

Bug Fixes

• Avoid blocking model launching when no system FFmpeg is available for TorchCodec (#47888). Previously import torchcodec raised a RuntimeError at import time when system FFmpeg was missing, which blocked startup (e.g. vllm serve Qwen/Qwen3-VL-2B-Instruct) even when TorchCodec was not in use. The error is now deferred to runtime so it only surfaces if TorchCodec is actually needed.
• Guard mixed-dtype allreduce RMSNorm quant fusions (#48330). The fused FlashInfer allreduce + RMSNorm + static-quantization patterns could match graphs where the activation and RMSNorm weight dtypes differ (e.g. a BF16 residual stream with an FP32 Gemma/Qwen-style RMSNorm weight in NVFP4 models), corrupting the hidden state and producing garbage output such as repeated !!!!! tokens. A dtype-match guard now routes incompatible mixed-dtype graphs to the safe path, while same-dtype models retain the full allreduce + RMSNorm + quant fusion.

Contributors

@Isotr0py, @hugo-cen

New Contributors

• @hugo-cen made their first contribution in #48330

vLLM v0.25.0 Release Notes

Highlights

This release features 558 commits from 232 contributors (64 new)!

• Model Runner V2 is now the default for all dense models (#44443). Building on quantized-model support from the previous release, MRv2 is now the standard execution path, with new support for EVS (#46535), realtime embeddings (#46762), prefix caching for Mamba hybrid models (#42406), multimodal-prefix bidirectional attention (#46942), and dynamic speculative decoding compatible with full CUDA graphs (#45953).
• PagedAttention has been removed (#47361). The legacy attention implementation is deleted now that V1/MRv2 backends are the standard path.
• The Transformers modeling backend is now as fast as native vLLM (#47187), and gained FP8 MoE support (#46820), CUDA graph + embed scaling fixes (#48010), and migration of GPTBigCode/Starcoder2 (#30966) and RoBERTa (#47452).
• New models: LLaVA-OneVision-2 (#44785), Unlimited OCR (#46564, #47102), MOSS-Transcribe-Diarize (#47729), openai/privacy-filter (#41026), and Hy3 (#47192). GLM-5 / DeepSeek-V3.2 landed in the model zoo (#46808) with GLM-5.2 tuning, and MiniMax-M3 gained pipeline parallelism (#45810) and NVFP4 support (#46756).
• New Streaming Parser Engine (#46610) — a unified tool-call/reasoning parsing framework, with a new Kimi k2.5/k2.6/k2.7 parser and ports of seed_oss (#46314) and DeepSeek V4 (#45877). The Rust frontend continues to mature with HTTPS/mTLS (#45890), a DP supervisor (#47076), and profiler control routes (#46306).
• Universal speculative decoding for heterogeneous vocabularies (TLI) (#38174), plus new DSpark (#46995) and DFlash (#46770, #46853) drafters.

Model Support

• New models: LLaVA-OneVision-2 (#44785), Unlimited OCR (#46564) with a Triton R-SWA backend (#47102), MOSS-Transcribe-Diarize (#47729), openai/privacy-filter (#41026), Hy3 with token-suffix and JSON Schema array support (#47192).
• GLM-5 family: GLM-5 / DeepSeek-V3.2 added to the model zoo (#46808), GLM-5.2 FP32 gate (#47410), GLM MTP post-final-norm fix (#47448), GLM4V startup fix (#47155).
• MiniMax-M3: pipeline parallelism (#45810), streaming reasoning parsing (#45718), and tok_sparse_select from MSA replacing Triton kernels (#47502).
• Transformers backend: now as fast as native vLLM (#47187), FP8 MoE fix (#46820), embed scaling + CUDA graph fix (#48010), GPTBigCode/Starcoder2 (#30966) and RoBERTa (#47452) migration, M-RoPE mm_token_type_ids fix (#46552), tied-embedding lm_head.bias fix (#46835).
• Voxtral: migrated to mistral-common 1.11.5 audio API (#46705) and realtime token-feedback hang fix (#44461).
• Gemma family: Gemma4 sliding-window/FA4 attention fixes (#47217, #47332), Gemma4 MTP quant_config fix (#47091); DiffusionGemma tensor parallelism (#45719) and HF stability-window semantics (#45965).
• Other fixes: MiniCPM-V 4.6 language-backbone LoRA (#46740) and placeholder grid fix (#45918), pooled Whisper sliding-window sizing (#47071, #47437), Mamba/Mamba2 checkpoint-without-architectures crash fix (#46037), DeepSeek-V2 hidden-size and aux-hidden-state fixes (#46986, #46973).

Engine Core

• Model Runner V2: default for all dense models (#44443); EVS (#46535), realtime embeddings (#46762), Mamba hybrid prefix caching (#42406), multimodal-prefix bidirectional attention (#46942), cross-attention warmup/block-table fixes (#46753, #47308), Mamba2 crash fix (#47428), scheduling slot accounting (#46974), model-ref cleanup on shutdown (#47483), bounded memory for large-logprobs requests (#46746).
• Speculative decoding: universal spec decode for heterogeneous vocabularies (TLI) (#38174); DSpark drafter + speculators checkpoint support (#46995, #47093); DFlash backend selection (#46770), per-layer RMSNorm fusion (#46761), CPU support (#44029), SWA+DFlash for MiMo (#46104), Laguna XS.2.1 drafter (#46853); MTP for Bailing hybrid models (#44880); block verification for rejection sampling (#46781); reduced TP communication for draft tokens (#46448).
• Sleep mode: pluggable sleep-mode backend abstraction (RFC #34303, #44074) with communicator-agnostic capability flags (#47243).
• Attention: FlashAttention block-size restriction removed for hybrid models (#36701), FLASH_ATTN_MLA_SPARSE Hopper sparse-MLA backend (#46189), DCP + FP8 KV cache in MLA decode (#44044), XQA decode kernels (#43232).
• KV offloading: tiering metric plumbing (#45959), request lifecycle fix (#46284), batched lookup in C (#46713), LookupResult enum (#46363).
• Misc: VLLM_GPU_SYNC_CHECK env var (#44800), VRAM semaphore infrastructure (#44465), skip detokenization in online beam search (#46422), several int32-overflow fixes in sampler/attention kernels (#46560, #47383, #47671).

Hardware & Performance

• GLM-5.2 / DeepSeek: fused_indexer_q_rope_quant Triton kernel (1.9–3.3% E2E throughput) (#46862), reduce-scatter MoE all-reduce (3.1–3.2% E2E) (#46635), op fusion for GLM5/DSV3.2 (#46876), token_to_req_indices cache for DSv4 (5–6x kernel speedup) (#47474), better DSv4 MXFP8 kernel (#47229), redundant-op removal (#47198, #46651).
• NVIDIA/Blackwell: FlashInfer fused all-reduce tuned for world_size=16 on GB300 (#46392), restored NVFP4 swizzled-scale zero-init to recover Blackwell decode throughput (#45739), CuTeDSL/FA4-MLA warmup infrastructure (#46182), skip cooperative top-K on SM120 (#47164), B12x backend for non-gated MoEs (#43328).
• Kernels: Helion fused_qk_norm_rope (#44010) and silu_and_mul_per_block_quant (#43994), Triton MLA logits workspace (#46819), swap-AB optimization for fused MoE (#36559), vectorized fp32 moe_sum supporting any top-k (#46643), blocking CUDA events to avoid busy-polling the driver lock (#47081).
• AMD/ROCm: moved to torch 2.11 stable ABI (#47128); AITER FlashAttention MLA prefill backend ROCM_AITER_FA (#45033); fused shared-expert for GLM-4.5/6/7 (#44313) and MiniMax-M3 (#46474, #46545); AITER MoE optimization for DeepSeek-V4 (#46122); AITER custom all-reduce in CudaCommunicator (#46065); INT3 quantization for quickreduce (#45666).
• Intel XPU: W8A8 FP8 linear kernel with multi-granularity quant (#43645), pipeline-parallel accuracy fix (#47253), uniform-batch CUDA graph for FA2 (#46555), route mm_prefix models to Triton attention (#47688), C++ get_memory_info (#47134).
• CPU: accelerated unquantized MoE for AArch64 (#46353), macOS/Apple Silicon hang fix via OpenMP (#46769) and broken-install fix (#47457), compressed-tensor w8a8 int8 MoE (#42920), Mamba ShortConv (#35059), chunked prefill + prefix caching for Qwen3.5 (#46202), faster gelu via tanh AOR (#44639).
• RISC-V: RVV path for W4A8 INT4 GEMM (#45269), BF16 on VLEN=256 hardware (#45243), reduced LMUL pressure in INT4 LUT dequant (#47538). POWER: fp16 support on PowerPC (#46135).
• Platform: accelerator-agnostic get_memory_info (#44825).

Large Scale Serving & Distributed

• Sequence parallelism without requiring DP, 1.9–5.0% E2E throughput improvement (#47070).
• Distributed: NCCL symmetric memory extended to AllGather and ReduceScatter (#46703), FlashInfer all-reduce defaults to MNNVL on single node (#47219, #47589), fault-tolerance backend to detect all2all peer faults and prevent corrupted output (#43637).
• Data parallel: throttle prefills based on local prefill work (#46532), rotate load-balancer tie-break to avoid engine bias (#47420), DP supervisor via the Rust frontend (#47076), DP MTP hang fix (#40589).
• PD disaggregation: secondary-tier implementation (#42285), Mooncake connector GDN (Qwen3.5) + MLA (DeepSeek-V4-Flash) support (#46807), NIXL Mamba1 support (#45019), MultiConnector kv_transfer_params merging (#46777), usage field exposed for disaggregated serving (#42748).
• DCP: FlashInfer MLA support (#43729), FLASHINFER_MLA_SPARSE support (#46076), LSE log-base fixes (#47079); Mooncake parallelized KV load (#45971) and DCP>1 lookup fix (#46855).
• ROCm: stabilized high-throughput DBO for DP+EP (#46990), EPLB for Quark OCP MXFP4 MoE (#47220).

Quantization

• 2/3/5/6/7-bit pack-quantized weight-only inference (Humming) (#46389), Triton INT4 per-token-head KV cache quantization (#40835).
• NVFP4: fused weight dequantization with compute in the MoE MLP Triton kernel (#44667), NVFP4 KV cache with skip-layers sliding window (#42890), MiniMax-M3 ModelOpt NVFP4 support (#46756).
• FP8: weights padding for per-block online quantization (#44763); deprecated the old FP8 online MoE quantization class (#44514).
• Marlin: thread-tile padding extended to MoE (WNA16 + FP8/MXFP8) (#45703), int8 grouped WNA16 MoE (#47154); FlashInfer MXINT4 MoE for gated SiLU (#46518).
• Fixes: W8A8 int-quant scheme-selection regression (#46860), tied quantized embeddings for ModelOpt Gemma4 (#45544), NVFP4+MTP crash on Qwen3Next (#46316), ModelOpt mixed-precision for sparse configs (#47318), CPU w4a8_int8 MoE path (#46739), actionable error on group-size/TP mismatch (#46230).

API & Frontend

• Streaming Parser Engine (#46610): unified tool-call/reasoning parsing with a new Kimi k2.5/k2.6/k2.7 parser; ported seed_oss (#46314) and DeepSeek V4 (#45877).
• OpenAI compatibility: Responses API namespace tools (#47024), per-request timing metrics field on Chat/Completions responses (#46768), token offsets on render endpoints (#44226), return_loss_mask for training-data generation (#46846), HTTP 422 for unprocessable image URLs (#47165).
• gpt-oss / Harmony: dedicated Harmony renderer (#46800), process_eos() flush (#46437), raw-output recovery on non-terminal parse (#47062, #47379).
• Rust frontend: static HTTPS and mTLS for HTTP and gRPC (#45890), DP supervisor (#47076), profiler control routes (#46306), repetition_detection sampling param (#46684), unified/combined parser interface (#46583), reduced multimodal tensor copies (#47581), plus many parser and validation fixes.
• Video: TorchCodec added as a video decoding backend (#46609).
• CLI/UX: TTFT and TPS printing in vllm chat (#46775), `mo...

vLLM v0.24.0 Release Notes

Highlights

This release features 571 commits from 256 contributors (77 new)!

• MiniMax-M3: Added support for the new MiniMax-M3 model (#45381), with a fast follow-on of BF16/FP8 indexer via MSA (#45892), MXFP4 support (#45896), FP8 sparse GQA (#45744), and extensive AMD/ROCm tuning — mxfp8 MoE/linear on gfx950 (#45725), fp8_per_channel for bf16 weights on MI300X (#45854), FP8 KV-cache fix (#45720), and packed-modules mapping (#45794). A MiniMax-M2 perf regression was also fixed (#45935).
• DeepSeek-V4 keeps maturing: Following its debut, DeepSeek-V4 received another large optimization pass — a FlashInfer sparse index cache (2–4% TTFT) (#45863), prefill chunk-planning optimization (4% E2E throughput) (#45061), a cluster-cooperative topK kernel for low-latency (#43008), contiguous per-block KV allocations (#44577), TEP=16 for the block-FP8 shared expert (#46001), and native DSA indexer decode for next_n > 2 on SM100 (#45322). It is now enabled on SM120 alongside GLM-5.1 (#43477), with XPU (#44144, #44517, #45240) and ROCm (#44899, #45103, #45681) attention/MoE paths added.
• Model Runner V2 (MRv2) continues to expand: MRv2 now supports quantized models by default (#44446), enables GraniteMoE by default (#45461), and gained migration of Qwen + DeepSeek-V2 MoE models (#42667), DFlash speculative decoding (#44586), and more accurate FP32 Gumbel sampling (#45996).
• Streaming Parser Engine: A new streaming parser engine unifies tool-call/reasoning parsing across models, with parsers for Qwen3 (#45413), MiniMax-M2 (#45701), GLM-4.7/5.1/5.2 (#45915), and Nemotron V3 (#45755).
• Diffusion LLMs: Added DiffusionGemma (#45163), including a CPU path (#45690) and structured-output guardrails for diffusion decoders (#45468).
• WideEP / DeepEP v2: Integrated DeepEP v2 for expert parallelism (#41183), with follow-on robustness fixes (#46404, #46432).
• Rust frontend matures further: Added API-key authentication (#44321), CORS (#45753), /tokenize + /detokenize (#44222), /pause /resume /is_paused (#44499), /abort_requests (#44382), /get_world_size (#44801), thinking_token_budget (#46137), a Python bridge for Rust tool parsers (#44624), and many new parsers and validation paths.
• Device selection change: vLLM no longer sets CUDA_VISIBLE_DEVICES internally; a new device_ids argument is provided instead (#45026). On ROCm, a deprecation window for CUDA_VISIBLE_DEVICES has begun (#46636).

Model Support

• New models: MiniMax-M3 (#45381), DiffusionGemma (#45163) + Gemma Diffusion on CPU (#45690), Hierarchical Reasoning Model — Text / HrmTextForCausalLM (#43098), OpenMOSS (#44124).
• Gemma 4: Unified FlashAttention (FA4) across all layers + mm_prefix support (#42175); many parser/serving fixes — forced-JSON skip for required/named tool choice (#45795), parsing with thinking disabled (#45832), streaming reasoning-state init (#45852), reasoning rendering on assistant turns (#45867), offline-parser truncation/token-leak fix (#45553); legacy Gemma4 parsers replaced with an engine-based implementation (#45588).
• DeepSeek-V4: OOM fix (#44914), MTP projection prefixing (#44821), supported KV-cache dtypes (#44892).
• Qwen / multimodal: Qwen3-VL video loader (#44412), Qwen2-VL/Qwen2.5-VL processor-mapped video loader (#45555), Qwen3-VL multi-video processing optimization (#46026) and multi-video crash fix (#46305), Qwen3-Omni VIT cu_seqlens device fix (#44264), fused qk-rmsnorm-rope-gate for Qwen3.5 (#44176), Qwen3.5 EP weight-loading fix (#45002).
• ViT full CUDA graph: GLM-4.1V (#40576), DeepSeek-OCR dual-path (#43586), Kimi-VL (#41992), mllama4 (#40660), Lfm2VL encoder (#44930).
• Other model fixes: Llama4 weight loading (#45047) and streamed loading to avoid host-OOM (#44645), MiMo v2.x QKV TP sharding + FP4 (#45200), ColQwen3.5 retrieval correctness (#46108), EXAONE-4.5 vision encoder (#45073), MiDashengLM TP>1 audio-encoder crash (#44408), MiniCPM-o/V device-placement and image-size fixes (#43844, #42332, #44980, #45244), Cohere2 MoE weight loading + parser (#44747, #44907), Nemotron V3 reasoning-as-content (#39091), ColBERT AutoWeightsLoader + query/document embedding io processor (#44999, #45210).
• Kernels: GLM-5 TRT-LLM ragged MLA prefill dimensions (#43525), GLM-5 router GEMM (#46385).

Engine Core

• Model Runner V2: Quantized models by default (#44446), GraniteMoE default (#45461), Qwen/DSv2 MoE migration (#42667), DFlash (#44586), simplified async output handling (#45442), attention-group split on num_heads_q (#45564), LoRA warmup fix (#35536), more accurate FP32 Gumbel sampling (#45996), min_tokens off-by-one fix in the V2 GPU sampler (#46243), plus assorted model/config compatibility fixes (#45868).
• Speculative decoding: Dynamic SD (#32374); DFlash with FlashInfer (#43081), mixed KV page sizes (#45181), and Qwen3Next targets (#45319); EAGLE3 support for Qwen3 (#43132); reduced TP communication for large-vocab drafts (#39419); race fix in async accepted counts (#45100); EAGLE multimodal encoder cache fixes (#46315).
• KV cache & scheduler: KV-cache watermark to reduce preemptions (#44594), two-phase allocation for cross-group prefix-cache hits (#44409), Marconi-style admission policy for hybrid cache (#37898), prefix-cache retention for Mamba/linear attention (#45845), DS Mamba tail-copy for MTP align mode (#45473), reduced scheduler copy overhead (#45840).
• Attention: Re-enabled cross-layer KV cache layout for MLA via stride-aware kernels (#45111), MLA prefill FA4 fp8 output (#43050), FlexAttention custom mask mods made fully cudagraphable (#45232), triton diff-kv backend for MiMo (#41797), FlashMLA sparse accuracy fix (#36616).
• Weight loading & core: fastsafetensors ParallelLoader for weight loading (#40183), release of cached device memory under pressure on UMA GPUs (#45179), structured outputs for beam search (#35022), device_ids arg / no internal CUDA_VISIBLE_DEVICES (#45026), graceful fallback when numactl --membind is blocked (#45438), config-class registration before tokenizer init (#40299), async scheduling with prompt embeds for multimodal models (#45673).

Large Scale Serving & Distributed

• Expert parallel: DeepEP v2 integration (#41183) with token-bound and topk-index fixes (#46404, #46432); NIXL EP — DBO with NIXL EP (#45275), top-k index dtype query (#45298), NVFP4 post-receive quantization skip (#45606), elastic-EP communicator (#45013); reject NCCL-based EPLB with async EPLB (#44978).
• KV connectors / disaggregated serving: KV push from prefill to decode via NIXL (#35264); per-region KV transfer classification for mixed full-attn + MLA groups (#44583); Mooncake pipeline-parallel PD support (#44528), async lookup (#45659), compact chunk-hash zero-copy lookup (#45969), SWA-block skipping (#45444); P/D fixes with DP supervisor (#46628) and DSV4 disaggregation (#45831); removed P2pNcclConnector (#44854).
• KV offloading: Multi-tier async batched lookup (#44193), packed HMA KV-cache layout (#46205, gated #46252), parallel-agnostic fs-tier cache (#44733), offloading-manager stats (#35669) and labeled/CPU-usage metrics (#45957, #45737), self-describing KV events (#43468), non-blocking idle flush (#45595), and numerous correctness/race fixes (#44784, #45823, #46231, #46278).
• Distributed core: Prefill step cadence for better non-PD DP balancing (#44558), KV-event map encoding (#42892), one-shot fused all-reduce PDL NaN fix (#45448).

Hardware & Performance

• NVIDIA / kernels: SM90 CUTLASS FP8 mm odd-M support via swap_ab (180–290% kernel speedup) (#44572), tuned fused_moe FP8 for Qwen3-Next-80B on H100 (+25%) (#44830), native DSA indexer decode on SM100 (#45322), cluster-cooperative topK for DeepSeek low-latency (#43008), PDL support for DeepGEMM (#46006), FlashInfer cutedsl NVFP4 GEMM (#42235) and cute-dsl MXFP8 linear kernel (#46393), new Helion kernels for FP8/RMSNorm quant (#36902, #33790, #36895, #34432).
• torch stable ABI: Continued (and completed) migration of kernels to the libtorch stable ABI — MoE [10c/n] (#44565), Marlin [11a/n] (#45176), Machete [11b/n] (#45304), final _C library migration [12/n] (#45415).
• AMD ROCm: Torch 2.11 (#45362); fused AR + RMSNorm + per-group FP8 quant (#42864), fused softplus-sqrt-topk MoE router under AITER (#44945), DSv4 flash-decode split-K kernel (#44899) and inverse-RoPE fusion (#45103), W4A16 FlyDSL MoE (#44400), A8W4 MoE CDNA4 swizzle gate for gpt-oss (#44804); deprecation window begun for CUDA_VISIBLE_DEVICES on ROCm (#46636).
• Intel XPU: Sequence-parallel support (#38608), torch-xpu 2.12 (#42262), vllm-xpu-kernels v0.1.10 (#40367), W4A16 int4 group_size=32 MoE (#45136), DeepSeek-V4 attention/MoE paths (#44144, #44517, #45240), top-p sampling correctness fix (#44470).
• CPU & other architectures: 2.5× faster ASR CPU preprocessing via multi-threading (#44612), CPU W4A16 INT4 MoE (#43409), cgroup memory-limit-aware KV cache sizing (#45086), RISC-V oneDNN W8A8 INT8 (#44478) and RVV micro-GEMM for WNA16 (#44324), pinned memory for WSL2 (#41496), ZenCPU runtime logging (#42726).
• TPU: tpu-inference upgraded to v0.22.1 (#45793).
• Misc perf: VLLM_TRITON_FORCE_FIRST_CONFIG to skip Triton autotuning (#42425), Triton recompile detection (#45631), fused multi-group block-table staged writes (#44944).

Quantization

• Online & mixed-precision: Online FP8 per-token-per-channel (PTPC) quantization (#44132); modelopt_mixed support extended to Ampere/SM80-86 (#45306) and Turing/SM75 (#45375).
• FP4 / MXFP: FlashInfer cutedsl NVFP4 GEMM backend (#42235) and cute-dsl MXFP8 linear kernel (#46393), MXFP4 W4A4 MoE CUTLASS E8M0 scale fix (#43557), SwiGLU clamp wired for NVFP4 MoE on non-Blackwell (#45836), flashinfer_cutlass allowed as a clamped NVFP4 MoE backend (#46492), NV...

vLLM v0.23.0 Release Notes

Please note that Minimax M3 is not yet supported in this version. Please follow vLLM recipe for usage guides for M3.

Highlights

This release features 408 commits from 200 contributors (63 new)!

• DeepSeek-V4 matures across backends: Following its introduction in v0.22.0, DeepSeek-V4 received another large hardening and optimization pass. Its sparse MLA metadata is now decoupled from DeepSeek-V3.2 (#44699), it gained a TRTLLM-gen attention kernel (#43827), EPLB support for the Mega-MoE (#43339), selective prefix-cache retention for sliding-window KV cache (#43447), and an index-share feature for DSA MTP (#44420). The model was also detached from torch.compile (#43746, #43891), its attention and RoPE paths were refactored (#44569, #44262, #43926), and an XPU attention decode path was added (#42953).
• Model Runner V2 expands to more dense models: MRv2 is now selected by default for Llama and Mistral dense models (#43458) in addition to Qwen3. It gained a FlashInfer sampler (#42472), breakable CUDA graphs (#44050), pipeline-parallel bubble elimination (#42187), kernel block-size support for hybrid models (#38831), and Gemma 4 MTP (#43241).
• Rust frontend grows up: The experimental Rust frontend added a streaming generate endpoint (#43779), dynamic LoRA endpoints (#43778), /version (#43854) and /server_info (#43942) endpoints, a server-router extension hook (#43774), request-ID headers (#43883), and many new tool parsers (InternLM2 #43481, hy_v3 #43872, Phi-4-mini #44213, Gemma4 #43850).
• Gemma 4: Added encoder-free Gemma 4 Unified support (#44429) and Gemma 4 MTP (#43241), plus numerous accuracy and startup fixes.
• Transformers v5 compatibility: vLLM now targets Transformers v5, with vendored MiniCPM-V/O processors (#44282) and compatibility fixes for Sarvam (#38804) and Voxtral (#44559).
• Multi-tier KV cache offloading: The offloading framework gained an object-store secondary tier (#41968), HMA enabled by default for capable connectors (#41847), tiering support for HMA models (#44287), and a per-request offloading policy via the on_new_request lifecycle hook (#43205).
• Unified parser: Reasoning and tool-call parsing are now unified behind a single Parser.parse() interface (#44267), with the Responses parser migrated to it (#42977).

Model Support

• New models: Step-3.7-Flash (#43859), Cosmos3 Reasoner (#43356), Gemma 4 Unified encoder-free (#44429), JetBrains Mellum v2 (#43992), Granite Speech Plus (#43519), Cohere Mini Code (#44707).
• Gemma 4: Encoder-free Unified support (#44429), MTP (#43241), native ViT linear layers (#43798), vision-embedder excluded from quantization (#44571), and fixes for MTP under TP>1 (#43909), block-table mismatch under concurrency (#43982), transformers-processor startup crash (#44232), and CPU init (#44615).
• Transformers v5: Vendor MiniCPM-V/O processors (#44282), Sarvam compat (#38804), Voxtral fetch_audio for transformers≥5.10 (#44559).
• Model fixes & enhancements: Qwen3-VL/Qwen3-omni-thinker deepstack accuracy under torch.compile (#43617), EVS for Qwen3-VL (#44205), GLM-5.1 PP loading (#42944), GLM-4.1V processor logits (#43575), GLM-4.6V video loader (#44417), OlmoHybrid init (#43846), HyperCLOVAX remote-code removal (#43860), Bailing-MoE rotary factor (#43770), Step3 PP residual KeyError (#37622), MiniCPM-V-4.6 video (#44509), MiniCPM-O audio unpadding (#38053), MiniCPM-V batched preprocessing (#44609), FunASR-Nano init (#44215), Cohere routing method (#44021), Kimi-K2.5 FlashInfer ViT metadata (#44493).
• Multimodal: Auto-select registered video loader for VLMs (#44126), O(log n) multimodal item handling per step (#44212), local image encoding in benchmarks (#43843), interleaved custom image benchmark datasets (#43636).
• Pooling/Classification: Proper exceptions for pooling UX (#44593), extra_repr() for pooler classes (#44805), LoRA-adapter-name pooling fix (#44410), resettled generative scoring entrypoint (#44153), expanded pooler unit tests (#43818, #44471).
• Refactor: AutoWeightsLoader for InternLM2 (#38278).

Engine Core

• Model Runner V2: Default for Llama and Mistral dense models (#43458), FlashInfer sampler (#42472), breakable CUDA graphs (#44050), removed Eagle's dedicated CUDA graph pool (#44078), pipeline-parallel bubble elimination (#42187), kernel block size for hybrid models (#38831), zeroing of freshly allocated KV blocks for hybrid + FP8 KV cache (#43990), actual batch max_seq_len for attention metadata (#43991), rejection-sampling acceptance-rate fix (#40651), KVConnector + PP cleanup (#43732), speculator-prefill warmup/capture (#44253).
• Speculative decoding (DFlash): Causal DFlash (#43445), proper lookahead-slot allocation (#43733), prefix-cache corruption fix (#42971); independent drafter attention-backend selection (#39930), attention-group split by num_heads_q for drafts (#43543), EAGLE/MTP lookahead caching in the SWA prefix-cache mask (#44082).
• Attention & hybrid/Mamba: FlexAttention/FlashAttention num-blocks-first layouts (#42095), OOT MLA prefill backend registration (#43325), FlashAttention upstream sync (#44065), Mamba LINEAR attention-module refactor (#43556), corrupted MLA + linear attention fix (#43961), KDA conv-state unification (#44539) and gate/cumsum fusion (#43667), Mamba SSD do_not_specialize (#43803), Qwen3.5 mixed prefill+decode split routing (#44700), MiniMax-M2 gate kernel (#38445).
• KV cache & scheduler: Pluggable KVCacheSpec (#37505), scheduler_block_size threaded into KVCacheManager/Coordinator (#44165), max_concurrent_batches moved to VllmConfig (#44274), config validation rejecting 0/negative knobs (#43794, #44057, #44207), KV-cache scale boilerplate removed from weight loading (#43167).
• Core: Freeze the garbage collector in workers after model init (#44363), sparse NCCL weight transfer for in-place updates (#40096), graceful spinloop ext-load failure handling (#43659), scheduled-function deprecations (#43358).

Large Scale Serving & Distributed

• KV cache offloading: Object-store secondary tier (#41968), HMA on by default for capable connectors (#41847) and tiering (#44287), per-request offloading policy (on_new_request) (#43205) and on_schedule_end() hook (#44206), token-offset selective offload (#39983), skip decode-phase blocks in CPU offload (#43797), page-size block alignment (#43689), Triton fast-path for small CPU→GPU swap_blocks_batch (#42212), stale sliding-window block fix (#42959).
• KV connectors / disaggregated serving: PP-aware handshake aggregation and intermediate-PP output plumbing (#43720), multiple-async-KV-load deadlock fix (#44560), Nixl Mamba prefix-caching mode (#42554), NixlConnector kv_both role deprecation cycle (#43874), Mooncake fixes (#43742, #44103, #42694), LMCache LMCacheMPConnector (#42865), EC connector shutdown API (#42423) and non-blocking lookup (#41627), KV-transfer tokens excluded from iteration_tokens_total (#43346).
• EPLB: Async EPLB by default (#43219), EPLB for DeepSeek-V4 Mega-MoE (#43339), Nixl zero-copy EPLB transfers (#41633).
• Data parallel: DP Ray placement groups on specific nodes (#44669) and grouped-node allocation fix (#43998), SSL for the DP supervisor (#43688), DP-coordinator startup timeout raised to 120s (#42343), per-GPU-worker RDMA NIC selection (#42083).

Hardware & Performance

• NVIDIA / kernels: FP8 FlashInfer attention for ViT (#38065), Triton MoE backend on Hopper by default (#44220), CUTLASS FP8 scaled-mm padding bypass (+20%) (#43706), MoE-permute buffer pre-allocation (+9–14%) (#43014), Fp8BlockScaledMM new_empty() optimization (#43677), TurboQuant shared dequant buffers (#40941), tuned selective_state_update for H200/RTX PRO (#44251), Inductor fast-path fallback for vLLM/AITER custom ops (#42129), Gemma RMS all-reduce fusion (#42646), NUMA auto-binding on DGX B300 (#43270).
• AMD ROCm: ROCm 7.2.3 (#43136), AITER v0.1.13.post1 (#44265), native W4A16 (#41394) and fused-MoE W4A16 HIP (#44075) kernels for RDNA3 (gfx1100), AITER top-k/top-p sampler by default (#43331), attention-sink support in AITER FA (#43817), AITER hipBLASLt GEMM online tuning (#40426), permute_cols for ROCm (#44674), blocks-first KV layout for AMD (#43660), N=5 wvSplitK for spec decode (#40687), MoRI connector improvements (#43303, #41751, #40344).
• Intel XPU: vllm-xpu-kernel v0.1.7 (#41019), block_fp8_moe (#42139), block-scaled W8A8 FP8 path (#39968), WNA16 oracle for GPTQ sym-int4 (#41426), rms_norm/act quant fusions (#43963), GDN-attention MTP (#43565), Triton selective-scan op (#43421), transparent sleep mode (#37149), CPU/tiering offloading on XPU (#36423), DeepSeek-V4 attention decode path (#42953).
• CPU & other architectures: zentorch-accelerated W8A8/W4A16 on AMD Zen CPUs (#41813), CPU top-k/top-p Triton sampling (#43633), non-divisible GQA decode in mixed batches (#43032), cpu_awq folded into awq_marlin (#43841), RISC-V RVV WNA16 helpers (#42730), fused GDN gated-delta-rule kernels (#43534), PowerPC SHM communicator (#43754), arm64 CI image (#41303).
• TPU: tpu-inference upgraded to v0.20.0 (#43394) then v0.21.0 (#44621).
• torch stable ABI: Continued migration of kernels to the libtorch stable ABI — merge_attn_states/mamba/sampler [8/n] (#43361), attention/cache kernels [9/n] (#43717), header files (#44013), cuda_view/silu_and_mul [10/n] (#44334), custom all-reduce/DeepSeek-V4 fused MLA/MXFP8 MoE [10b/n] (#44365); ROCm fallback to regular ABI (#44648), _has_module trial-import verification (#44035).

Quantization

• ModelOpt: LM-head quantization (#42124), MXFP8 non-gated MoE (#42958).
• compressed-tensors: WNA8O8Int linears and WNInt embeddings (#44340), asymmetric MoE WNA16 Marlin (#44025), single-class NVFP4 linear ref...

Highlights

This release features 8 commits from 6 contributors (1 new)!

v0.22.1 is a patch release on top of v0.22.0 with targeted bug fixes plus a couple of additions: new model support for JetBrains' Mellum v2, zentorch-accelerated quantized linear inference on AMD Zen CPUs, and fixes for multi-node Ray data-parallel serving, DeepSeek-V4 initialization, and a few model-loading regressions.

Model Support

• New model: JetBrains' Mellum v2, an open-weights Mixture-of-Experts code-generation model (#43992).
• DeepSeek-V4: resolve a CUTLASS fmin compatibility issue that broke initialization (0decac0).
• Fix OlmoHybridForCausalLM failing to initialise after the checkpoint changed rope_parameters from None to {"rope_type": None} (#43846).
• Fix HyperCLOVAX loading after the upstream HuggingFace repo removed its remote code (now native in transformers >= 5.9.0): register the hyperclovax model_type so vLLM uses its vendored config instead of the stale auto_map (#43860).

Hardware & Performance

• AMD Zen CPUs: route W8A8 (int8 dynamic-symmetric) and W4A16 (GPTQ) linear inference through zentorch kernels, registered ahead of the generic oneDNN CPU kernels, with transparent fallback on non-Zen CPUs, GPUs, and XPU (#41813).

Large Scale Serving

• Fix a deterministic hang in multi-node Ray data-parallel serving with num_api_servers > 1 by excluding the Ray DP backend from the deferred (kernel-assigned) port allocation introduced in #42585 (#43864).

Build & CI

• Docker: stop installing flashinfer-jit-cache via --extra-index-url while it is quarantined on PyPI, fixing image builds (#44366).
• Normalize NIXL KV-connector wheel installs so only the wheel matching the image's CUDA major is kept, fixing ImportError: libcudart.so.12 when importing nixl_ep on CUDA 13 images (#44266).

Contributors

@khluu, @vadiklyutiy, @aadwived, @shadeMe, @alec-flowers, @hmellor

New Contributors

• @aadwived made their first contribution in #41813

Highlights

This release features 459 commits from 230 contributors (63 new)!

• DeepSeek V4 maturity: DeepSeek V4 received a major hardening pass this cycle — the model was reorganized into a dedicated vllm/models/deepseek_v4/ package (#43004, #43039, #43073, #43077, #43149), gained NVFP4 fused MoE support (#42209), full + piecewise CUDA graph (#42604), and MTP speculative decoding (#43385). A large set of fused kernels (MegaMoE, mhc, Q-norm, indexer, sparse MLA) and ROCm parity fixes landed alongside accuracy fixes (#42810, #43710).
• Model Runner V2 advances toward default: MRv2 is now default for Qwen3 dense models. vLLM will fall back to MRv1 for features that aren't yet supported in MRv2 (#39337). sleep-mode weight reload (#42673), update_config (#42783), and shared KV-cache layers (#35045), plus many correctness fixes.
• Experimental Rust frontend: A new Rust front-end integration landed (#40848), with the implementation moved into the tree (#43283) and a DP Supervisor for data-parallel serving (#40841).
• Batch invariance, faster: Batch-invariant inference gained Cutlass FP8 support for a 28.9% end-to-end latency improvement (#40408), compile-mode support on SM80 (#42456), and an NVFP4 Cutlass linear path (#39912).
• Multi-tier KV cache offloading: A new multi-tier KV cache offloading framework (#40020) with a Python filesystem secondary tier (#41735), DSv4 support (#43142), and Mooncake disk offloading (#42689) extends offloading beyond CPU memory.

Model Support

• New architectures: MiniCPM-V 4.6 (#41254), InternS2 Preview (#42705), OpenVLA (#42654), MolmoWeb hf_overrides docs (#42163); EXAONE-4.5 aligned with Transformers update (#42246).
• Speculative decoding: custom callable proposer backend (#39487), post-norm EAGLE-3 speculators (#42764), peagle speculators (#41826), hybrid-attention models in extract_hidden_states (#39949), non-MTP speculation for NemotronH (#43130), shared MTP weights in MRv2 (#42538).
• DeepSeek V4: NVFP4 MoE (#42209), CUDA graph full/piecewise (#42604), MTP (#43385), model package refactor (#43004, #43039, #43073, #43077), sparse MLA + compressor refactor (#43149, #43710), MegaMoE input-prep kernel move (#43632).
• Qwen3.5/3.6: GDN output-projection flatten (#42311), GatedDeltaNet Marlin TP≥2 fix (#36329), ViT full CUDA graph (#42151), runai-streamer weight loading for Qwen3.5/MTP/Qwen3-VL (#42521, #42716), KDA chunk-prefill exp2 semantics (#43195).
• Gemma3/Gemma4: mixed-resolution image co-batching crash fix (#42217), MoE routing closure fix (#42250), tool-parser float-corruption fix (#42128), batched vision encoder for image/video (#43169), multi-GPU fix (#42630).
• Kimi-K2.5: skip vision-tower dtype conversion under quantization (#42869), mm_projector dtype fix (#42081).
• Cohere: enable Cohere MoE (#43143), pipeline parallelism for Cohere vision (#42819).
• Tool calling: Apertus tool parser (#41154), Qwen3Coder anyOf/oneOf/$ref resolution re-land (#37831), shared coerce_to_schema_type across MiniMax-M2 / DeepSeek-V3.2 / Seed-OSS parsers (#43006, #43019, #43140).
• ViT CUDA graph: Qwen2-VL (#41736), Step3-VL encoder (#42224), Qwen3.5 (#42151), FlashInfer metadata for Qwen2.5-VL vision attention (#42787).

Engine Core

• Model Runner V2: Qwen3-dense-by-default oracle (#39337), sleep-mode reload weights (#42673), update_config (#42783), shared KV-cache layers (#35045), FP32 gumbel sampling (#41775), auto-fallback to MRv1 with connectors (#42955), logprob_token_ids correctness (#43125, #41761), prompt-logprobs size fix (#42778).
• KV offloading: multi-tier framework (#40020), Python filesystem secondary tier (#41735), DSv4 support (#43142), tier-offload follow-up (#42529), prefer HND layout (#41928), reset_cache() (#41956), per-request tracking (#42507), store-deferral fix (#41945).
• MoE refactor: ExpertMapManager (#41046), experts moved to experts/ (#42334), RoutedExperts alias for FusedMoE (#40735), EPLB refactoring for FusedMoE (#41055).
• Mamba: attention module refactor (#41126), Mamba2 SSD kernel warmup (#39822), bf16 SSM cache (#41680), GPU-side state postprocessing fused kernel (#40172), run single-token extends as decodes (#42430).
• KV events: emit KV cache metadata (#40984).
• Allocator: manual cumem allocator enable (#33648), stream-aware free callback (#43020).
• elastic-EP: stage/commit MoE quant method on reconfigure (#40881).

Hardware & Performance

• NVIDIA Blackwell / SM12x: FlashInfer b12x MoE + FP4 GEMM for SM120/121 (#40082), per-tensor FP8 CUTLASS on SM12.1 (#41215), head_dim=512 for FlashInfer TRTLLM attention (#38822), FlashInfer Blackwell GDN prefill (#40717), GDN prefill kernel for SM100 (#43273).
• Performance: batch-invariant Cutlass FP8 (+28.9% E2E) (#40408), CutlassFP8 padding pre-processing (+13.5% TTFT) (#42651), padded NVFP4 quant kernel (+2.4–5.7% E2E) (#42774), GPU<->CPU sync elimination 1/n (#41429) and 4/n (#42347), fused RoPE+KVCache+q_concat for MLA (#40392), MLA compute_prefill_context / _v_up_proj optimizations (#42460, #42561), penalties Triton kernel (#40657), do_not_specialize in fused FP8 RoPE (#42849), FULL CUDA graph capture for TRITON_MLA decode (#42885).
• AMD ROCm: DSV4 functionality + accuracy fixes (#42810, #43679 Tilelang MHC), flash sparse MLA Triton kernels (#41812), gluon paged MQA logits on gfx950/MI355X (#42062), RMSNorm+Quant fusion for gfx950 (#41825), AITER FA backend cleanup (#41942), XGMI backend for MoRI connector (#41753), QuickReduce min-size override (#41675), DSV4 MTP (#43385).
• CPU / RISC-V: RVV-optimized attention kernels for RISC-V Vector Extension (#40119) with VLEN=256 (#42943), fused GDN for AMX CPU (#42707), MXFP4 W4A16 MoE (#41922), experimental Triton + MRv2 on CPU (#43225), improved CPU thread utilization (#42666), --cpu-distributed-timeout-seconds (#42968).
• Intel XPU: GPTQ int4 support (#37844), mxfp8 MoE (#41918), FP8 block-scaled quantization (#42952), custom-op collective behavior (#41354), multiple sparse-attention kernels (#37888), MoE topk routing + MXFP4 fallback (#42951), CT W4A4 MXFP4 path (#38896), reduced XPU MoE host overhead (#42915).
• Kernel ABI: continued migration to libtorch stable ABI — 5/n (#42339), 6/n (#42663), 7/n (#43209).
• Experimental: breakable CUDA graph (#42304).

Large Scale Serving

• Disaggregated serving (NIXL): lease-renewal TTL for KV blocks on P (#41383), handshake-failure policy honoring (#40364), GDN support for PD with NIXL (#41869), multi-node TP>8 fix (#39907), side-channel host-selection fix (#41806).
• Mooncake: disk offloading in MooncakeStoreConnector (#42689), HMA support for DSV4 (#42828), operation metrics (#43392), load-failure propagation (#42788), block-aligned full hits (#43494), finish-after-preemption handling (#43281).
• Data parallel: DP Supervisor (#40841), publish request counts at engine-step start (#41626), forward X-data-parallel-rank header (#42330).
• EPLB: change default EPLB communicator (#43110), VLM-wrapper init fix (#39805), remove dead torch.accelerator.synchronize() (#40733).
• LoRA: one-shot Triton kernel for MoE LoRA (#42290), simultaneous 2D & 3D MoE LoRA adapters (#42242), reduced 2D-weight memory under EP (#42737), MoE LoRA align-kernel grid fix (#40131).

Quantization

• MXFP4: linear layers + compressed-tensors integration (#41664), CPU W4A16 MoE (#41922), XPU mxfp8 MoE (#41918).
• NVFP4: DeepSeek V4 fused MoE (#42209), ModelOpt W4A16 NVFP4 fused MoE + mixed-precision dispatch (#42566), batch-invariant NVFP4 Cutlass linear (#39912), FlashInfer TRTLLM NvFP4 monolithic MoE routing fix (#43223), TRTLLM NVFP4 MoE chunking fix (#43599).
• Quark: load Quark NVFP4 checkpoints (#35859), W8A8 INT8 garbage-output fix on Step-3.5-Flash (#41892), W4A4 oracle refactor (#41436).
• AutoRound: W4A16 support (#39778).
• ModelOpt: Qwen3.5/3.6 VLM quantized prefix mapping (#42546).
• Framework: rework quantization_config to use QuantKey with activation override (#41566), MoE W4A8 CT migrated to oracle (#42680), AWQ Marlin MoE onto modular WNA16 oracle (#42483), GPTQ consolidation (gptq_marlin → auto_gptq) (#38288).

API & Frontend

• Rust frontend: integration (#40848), in-tree code move (#43283), utility call-ID newtype (#43405), simplified AuthenticationMiddleware path extraction (#43426).
• Responses API: chat_template_kwargs support (#42272), message-merging fix (#42189), empty channel/recipient harmony fix (#35540).
• Completions: thinking_token_budget support (#42116) with inverted-condition fix (#41674); map reasoning_effort to enable_thinking (#43401).
• Frontend: truncation side for OpenAI endpoints (#43260), normalize reasoning_content → reasoning (#42664), reworked fastokens integration (#43168), consolidated Speech-to-Text entrypoints (#42370, #42274), beam-search consolidation via BeamSearchMixin (#42946), score/rerank chat-template instructions (#42412).
• Auth: API-key authorization for /v2 endpoints (#42594).
• Offline API: pooling offline API split into PoolingOfflineMixin (#42267), split offline inference APIs/utils (#43553).

Build & Dependencies

• CUDA 12.9 wheel builds switched to PyTorch manylinux_2_28 base (#41668).
• FlashInfer bumped to v0.6.11.post2 (#41711); nvidia-cutlass-dsl to 4.5.2 (#42991, #43230, #43745); llguidance to 1.7 (#42150); triton_kernels downgraded to v3.5.1 for gpt-oss (#43135).
• Rust frontend build: setuptools-rust dependency (#43287, #43377), pinned protoc in rust-build stages (#43292).
• Docker: non-root vllm-openai target (#40275), build mooncake-transfer-engine from source (#42114), AINIC & Thor NIC support (#40453); Python-only installation made optional (#42293).
• vllm-tpu: disable build isolation for CUDA deps (#43038), tpu-inference docker build fix (#43360).
• humming MoE backend dependency adde...

Highlights

This release features 367 commits from 202 contributors (49 new)!

• Transformers v4 deprecated: This release formally deprecates transformers v4 support (#40389). Users should migrate to transformers v5.
• C++20 build requirement: vLLM now requires a C++20-compatible compiler for compatibility with PyTorch (#40380). This is a breaking build change.
• KV Offload + Hybrid Memory Allocator (HMA): The KV offloading subsystem now integrates with the Hybrid Memory Allocator, including scheduler-side sliding window group support and full HMA enablement (#41228, #41445, #39571).
• Speculative decoding with thinking budget: Speculative decoding now respects reasoning/thinking budgets, enabling correct spec decode for reasoning models (#34668).
• TOKENSPEED_MLA backend on Blackwell: A new TOKENSPEED_MLA attention backend is available for DeepSeek-R1/Kimi-K25 prefill + decode on Blackwell GPUs (#41778).

Model Support

• New architectures: MiMo-V2.5 (#40967), Laguna XS.2 (#41129, #41880), Moondream3 (#32325), Qianfan-OCR (#40136), Cohere MoE (#40817), Cohere Eagle (#42078).
• Speculative decoding: EAGLE for Mistral (#41024), Gemma4 MTP (#41745), MTP for MiMo-V2.5 (#41905), Cohere Eagle (#42078).
• DeepSeek V4: AMD/ROCm support (#40871), pipeline parallelism (#41694), max reasoning effort (#40982), disaggregated serving fixes (#41957).
• Tool calling: Cohere reasoning and tool parsers (#40422), LFM2/2.5 tool parser (#39243).
• Gemma3/Gemma4: hidden_act variant support (#40588), pipeline parallelism fix (#40786), MoE fixes (#41206, #41574, #41401), tool parser crash fix (#41991, #42188).
• Model Runner V2: Qwen3.5/Mamba hybrid model support (#35520), logprob_token_ids support (#40559).
• CUDA graph: ViT CUDA graph support for Qwen2.5-VL (#40830).
• Compatibility: Vendor HCXVisionConfig for Transformers v5 (#38447), legacy rope_type checkpoint support (#41734).

Engine Core

• KV offloading + HMA: Scheduler-side sliding window groups (#41228), full HMA enablement (#41445), multi-connector HMA (#39571), per-job store completion (#39186), DCP/PCP support in OffloadingConnector (#41549), MooncakeStoreConnector for distributed KV offloading (#40900).
• Speculative decoding: Thinking budget support (#34668), independent drafter attention backend selection (#39930), multimodal model support with warning (#41752), per-step allocation elimination (#41043).
• Model Runner V2: Rejection sampling acceptance rate fix (#40651), skip metadata rebuild before draft prefill (#40410), rebuild metadata between draft decode steps (#41162), Qwen3.5/Mamba hybrid support (#35520).
• Routing: Replace routing replay with device cache and async D2H pipeline (#39917).
• Ray: RayExecutorV2 enabled by default (#41421), actor name collision fix for DP > 1 (#40398).
• Stability: Two-phase pause to prevent scheduler deadlock (#39366), thread-safe HF tokenizer wrappers (#41181), OOM prevention via max_split_size_mb during model loading (#41268).
• IndexCache support for DSA models (#37735).

Hardware & Performance

• NVIDIA Blackwell: TOKENSPEED_MLA backend for DSR1/Kimi-K25 (#41778), faster per-token FP8 group quant packed kernel (#41326), FP8 on NVIDIA Thor/SM110 (#39712), CUTLASS scaled mm for non-compatible sizes (#41868).
• Performance: FlashInfer top-k/top-p sampler enabled by default (#40376), FP8 FlashInfer attention for ViT (#38065), TurboQuant shared dequant buffers (#40941), AllPool.forward 51% faster (#41163), GPU<->CPU sync elimination in pooling (#41433) and attention (#41434), numpy zero-copy embedding serialization (#41681), multimodal processor skip for text-only (#41246), FlashInfer FP8 async TP fusion (#39505), NVFP4 all-gather GEMM fusion for AsyncTP (#41882), re-enable allreduce+RMS fusion for DP/PP (#41458), DeepSeek bf16→fp32 via torch.mm (#41300), persistent MLA for sparse backend (#41990), configurable safetensors checkpoint prefetch (#41499), fused mhc_post_pre kernel (#41536), 2D-grid W8W8 group quant kernel (#42153), relaxed memory ordering for KV cache swaps (#39306).
• AMD ROCm: ROCm 7.2.2 (#41386), DBO (Dynamic Batch Optimization) (#34726), AITER Fused Allreduce+RMSNorm (#37646), Fused Shared Expert (FSE) for Qwen3-Next (#39280), DeepSeek V3.2 TP4 AITER MLA (#41835), GDN linear attention fusion (#40711), eliminate redundant MoE buffer copies in AITER (#41713), CPU offloading support (#40549), DeepEP API update (#39721), cap Triton paged attention block size to fix shared memory OOM (#38502).
• CPU: FP8 attention for AMX/AVX-512 (#39445), FP8 W8A16 linear (#41186), FP8 W8A16 MoE (#41314), DNNL AVX2 W8A8 Int8 (#41318), Gated DeltaNet Attention for Qwen 3.5/3.6 (#41025), RISC-V OMP thread auto-binding (#40569).
• Intel XPU: Top-k/top-p sample kernel (#39285), out-of-place all-reduce (#41808), LoRA support (#38206).
• IBM Power: VSX attention backend (#40451).
• FlexAttention: Re-enabled for batch invariant mode (#40842).
• MLA: Abstracted MLA prefill backends, eliminated cuDNN dependency (#32623).

Large Scale Serving

• Disaggregated serving: Bi-directional KV cache transfers between P and D (#32553), NIXL transfer redesign (#40731), EPLB memory overhead optimization (#40013), NIXL connector bumped to 1.x (#42364), Mooncake KVConnectorStats for transfer observability (#40414), NIXL P-node pre-admission rejection notification (#41269), KV block release for skipped P-ranks (#40449).
• DCP: Pack output and LSE in DCP A2A (#41160).
• MoE: PluggableLayer interface for out-of-tree MoE runners (#35178).
• LoRA: Initial expert parallel (EP) support (#40867), Qwen3.5 LoRA fusion fix (#37912).

Quantization

• NVFP4: KV cache support (#40177), Triton dequant/QDQ emulation kernels for Hopper and AMD (#40033), GELU on TRT-LLM NvFP4 fused MoE for Gemma4 (#41050), ModelOpt NVFP4 W4A16 (#41769), NVFP4 all-gather GEMM fusion for AsyncTP (#41882), GLM4-MoE NVFP4 loading fix (#41755).
• MXFP4: Humming MXFP4 MoE backend (#41083), FlashInfer CUTLASS MXFP4-MXFP8 MoE fix (#42089).
• TurboQuant: Hybrid model and uniform quantization support (#39931).
• Compressed tensors: Allow configs with non-explicit ignores (#41965).
• FP8: Bias loading fix (#41424), FlashInfer autotune temporarily disabled for correctness (#41524).
• DSV4: Improved fused Indexer Q quant kernel (#41428).

API & Frontend

• Responses API: Streaming tool/function calling with required (#40700) and named tool/function choice (#41110), resubmitting output items with missing fields (#41355).
• OpenAI compatibility: system_fingerprint field in responses (#40537), prompt_embeds content part support (#40720), defer_loading and tool_reference support (#40190), rendered prompt text in chat completion response (#42052), tolerate empty content in forced tool choice (#40148).
• Tool calling: XGrammar 0.2.0 with structural tags for strict tool calling + reasoning (#40894), Cohere reasoning/tool parsers (#40422), LFM2/2.5 tool parser (#39243).
• Tokenizer: Fastokens support (#41741).
• RLHF: Explicit /start_weight_update and /finish_weight_update APIs (#39212).
• ASR: Engine request abort on cancellation (#41266).
• Configuration: VLLM_SKIP_MODEL_NAME_VALIDATION env var (#34676), configurable model weights loading tracking (#41086), Triton JIT compilation monitor (#40137).

Build & Dependencies

• Breaking: C++20 required for PyTorch compatibility (#40380).
• Breaking: Transformers v4 deprecated (#40389).
• Docker image size reduced by ~2.5 GB via deferred FlashInfer cubin download (#41134).
• CUDA 13.0 wheels switched to PyTorch manylinux_2_28 base (#41416).
• DeepGEMM bundled wheel built per-Python for CPython compatibility (#41516).
• Container image provenance metadata embedded (#40653).
• tpu-inference upgraded to v0.19.0 (#41844).
• NIXL connector bumped to 1.x (#42364).
• ROCm 7.2.2 (#41386).

Contributors

@AndreasKaratzas, @haosdent, @khluu, @yewentao256, @stecasta, @mgoin, @Isotr0py, @hmellor, @chaunceyjiang, @jeejeelee, @noooop, @MatthewBonanni, @njhill, @zyongye, @yzong-rh, @ronensc, @NickLucche, @chaojun-zhang, @dzhengAP, @chfeng-cs, @TheEpicDolphin, @esmeetu, @wzhao18, @ZJY0516, @juliendenize, @kylesayrs, @fadara01, @Etelis, @tianmu-li, @arpera, @ekagra-ranjan, @orozery, @wxsIcey, @jikunshang, @izhuhaoran, @rasmith, @russellb, @Lucaskabela, @Harry-Chen, @alec-flowers, @pmaybank, @Terrencezzj, @hickeyma, @Baekpica, @itej89, @fxmarty-amd, @WoosukKwon, @juhi10071998, @sychen52, @baonudesifeizhai, @vllmellm, @johncalesp, @the-david-oy, @lucianommartins, @bittoby, @Dao007forever, @lyd1992, @yuwenzho, @lesj0610, @sfeng33, @micah-wil, @akii96, @yma11, @SoluMilken, @mmangkad, @SiluPanda, @ojhaanshika, @zhandaz, @bhoomit, @simon-mo, @msanft, @angelayi, @anthonsu, @artem-spector, @zhangxin81, @benoittgt, @joerowell, @yangrz7, @chelnnexy, @liangel-02, @walterbm, @rishitdholakia13, @SKRohit, @BugenZhao, @JaredforReal, @amd-lalithnc, @frgossen, @h-avsha, @DarkLight1337, @danisereb, @laithsakka, @Bortlesboat, @wangluochao902, @Rohan138, @hao-aaron, @puririshi98, @roikoren755, @heachary, @UranusSeven, @dsingal0, @ChenxiQ, @snadampal, @ilmarkov, @wendyliu235, @lequytra, @JisoLya, @LuisRobaina, @sniper35, @eicherseiji, @Yuyi-Ao, @raviguptaamd, @sungsooha, @ganyi1996ppo, @andylolu2, @FredericOdermatt, @ProExpertProg, @rbrugaro-amd, @mcsantiago, @hnt2601, @jinzhen-lin, @taneem-ibrahim, @tomeras91, @alex-jw-brooks, @Aktsvigun, @HanFa, @netanel-haber, @JasonKeyiL, @gshtras, @joa-stdn, @Seven-Streams, @JartX, @xuechendi, @BowenBao, @Akashcodes732, @jeffreywang-anyscale, @czhu-cohere, @zhewenl, @marvinzh, @Lidang-Jiang, @gcanlin, @whx-sjtu, @S1ro1, @liulanze, @Dhruvilbhatt, @laviier, @wi-adam, @aaab8b, @yuankaichen-amd, @ZhanqiuHu, @QwertyJack, @viktorpusTT, @divakar-amd, @starkwj, @benchislett, @jcyang43, @JLiu4Coding, @xy3xy3, @hongxiaya...

vLLM v0.20.2

Highlights

This release features 6 commits from 6 contributors (0 new)!

This is a small patch release with bug fixes for DeepSeek V4, gpt-oss, and Qwen3-VL

Bug Fixes

• DeepSeek V4 sparse attention: Re-enable the persistent topk path on Hopper and ensure the memset kernel runs at CUDA graph capture time regardless of max_seq_len, fixing the MTP=1 hang on DeepSeek V4 (#41665, revert of #41605).
• DeepSeek V4 KV cache: Fixed a "failure to allocate KV blocks" error in the V1 engine KV cache manager (#41282).
• gpt-oss MXFP4 + torch.compile: Plumbed hidden_dim_unpadded through the moe_forward fake op so MXFP4 works under torch.compile on v0.20.x (#42002, backport of #41646).
• Qwen3-VL: Removed an invalid deepstack boundary check that could fail under heavy load (#40932).

Contributors

@ywang96, @zyongye, @stecasta, @wzhao18, @Isotr0py, @khluu

vLLM v0.20.1

This is a patch release on top of v0.20.0 primarily focused on DeepSeek V4 stabilization and performance improvements, along with several important bug fixes.

DeepSeek V4

• Base model support (#41006).
• Multi-stream pre-attention GEMM (#41061), configurable pre-attn GEMM knob (#41443), and tuned default VLLM_MULTI_STREAM_GEMM_TOKEN_THRESHOLD (#41526).
• BF16 and MXFP8 all-to-all support for FlashInfer one-sided communication (#40960).
• PTX cvt instruction for faster FP32->FP4 conversion (#41015).
• Integrated tile kernels (head_compute_mix_kernel) for optimized head computation (#41255).
• Guard megamoe flag with Pure TP (#41522).
• Fixed persistent topk cooperative deadlock at TopK=1024 (#41189) and inter-CTA init race on RadixRowState (#41444), with temporary disable of persistent topk as a workaround (#41442).
• Fixed import error due to AOT compile cache loading (#41090).
• Fixed torch inductor error (#41135).
• Fixed repeated RoPE cache initialization (#41148).
• Fixed missing type conversion for non-streaming tool calls in DSV3.2/V4 (#41198).

Bug Fixes

• Fixed max_num_batched_token not being captured in CUDA graph (#40734).
• Fixed num_gpu_blocks_override not accounted for in max_model_len checks (#41069).
• Auto-disable expandable_segments around cumem memory pool (#40812).
• Fixed BailingMoE linear layer (#40859) and MLA RoPE rotation for BailingMoE V2.5 (#41185).
• Fixed reasoning parser kwargs not being passed to structured output (#41199).
• [ROCm] Fixed input_ids and expert_map args for Quark W4A8 GPT-OSS (#41165).

List of contributors

@BugenZhao, @chaunceyjiang, @gau-nernst, @ghphotoframe, @Isotr0py, @jeejeelee, @khluu, @njhill, @Rohan138, @wzhao18, @youkaichao, @ywang96, @ZJY0516, @zixi-qi, @zyongye

vLLM v0.20.0

Highlights

This release features 752 commits from 320 contributors (123 new)!

• DeepSeek V4: Initial DeepSeek V4 support landed (#40860), with DSML token-leakage fix in DSV4/3.2 (#40806), DSA + MTP IMA fix (#40772), and a silu clamp limit on the shared expert (#40950).
• CUDA 13.0 default: Default CUDA wheel on PyPI and vllm/vllm-openai:v0.20.0 image switched to CUDA 13.0; architecture lists and build-args cleaned up (#39878), and CUDA bumped to 13.0.2 to match PyTorch 2.11.0 (#40669). As a general rule of thumb, our CUDA version policy follows PyTorch's. We highly recommend to install vLLM with uv and use --torch-backend=cu129 if you are on CUDA 12.9.
• PyTorch 2.11 upgrade (#34644): vLLM ships on torch 2.11 for CUDA, and XPU is now also on torch 2.11 (#37947) — XPU is no longer pinned to 2.10. This is a breaking change for environment dependency.
• Python 3.14: Added to the supported Python version list (#34770).
• Transformers v5: vLLM now runs on HuggingFace transformers>=5 (#30566), with vision-encoder torch.compile bypass (#30518) and continued v4/v5 compat fixes including PaddleOCR-VL image processor max_pixels (#38629), Mistral YaRN warning (#37292), and Jina ColBERT rotary inv_freq recompute (#39176).
• New large models: Hunyuan v3 (Hy3) preview (#40681) with HYV3 reasoning parser (#40713); Granite 4.1 Vision as a built-in multimodal model (#40282).
• FlashAttention 4 as default MLA prefill: FA4 re-enabled as the default MLA prefill backend (#38819) with head-dim 512 and paged-KV support on SM90+ (#38835), plus an upstream FA4 sync (#38690).
• TurboQuant 2-bit KV cache: New attention backend delivering 2-bit KV cache compression with 4× capacity (#38479), now with FA3/FA4 prefill support (#40092).
• Online quantization frontend: New end-to-end online quantization frontend (#38138), with docs (#39736); experts_int8 consolidated into the FP8 online path (#38463); MXFP8 online quant moved to the new frontend (#40152).
• vLLM IR: Initial IR skeleton with rms_norm op (#33825), OOT-platform kernel imports (#38807), gemma_rms_norm reworked on IR (#39014), and IR op testing/benchmarking infra added (#40167) — foundation for future kernel work.
• Model Runner V2 advances: Eagle prefill full-CUDA-graph (#37588), auto-resolve cudagraph mode/sizes from attention backend (#32936), fused probabilistic rejection sample kernels (#38496), config validation for unsupported features (#38758), piecewise-fallback disabled for eagle draft decodes (#39773), multiple prompt-logprobs support (#39937), prefill warmup coverage (#40746), and a fix for accuracy regression caused by stale sampled/draft tokens (#39833).
• MoE refactor series: Unquantized migrated to Full Oracle Flow (#36286), CT W8A8 to Oracle (#39187), SharedExperts class (#35153), SharedFusedMoE removed (#35782), DefaultMoERunner split (#35326) and later combined back into MoERunnerBase (#40560), shared/fused expert output sum moved into MoERunnerBase (#35949), ZeroExpertFusedMoE in new framework (#35549), compressed_tensors_moe.py split (#38960), GPTQMarlinMoEMethod reworked with MK (#37990), XPU & CUTLASS MoE relocated to fused_moe/experts/ (#40568, #40574), make_expert_params_mapping renamed (#40671), MoE LoRA refactor (#40338), and MoE DP chunking removed (#39107).
• Performance: Optimize batch invariant with fused rms norm — 2.1% E2E latency improvement (#40413); avoid seq_lens_cpu GPU→CPU sync (#40654); cache InductorPass.hash_source (#39328); skip FX-graph deserialization on loading for faster warm compile (#40151); CUDAGraph memory profiling enabled by default for clearer startup memory accounting (#38284).

Model Support

• New architectures: DeepSeek V4 (#40860), Hunyuan v3 preview (#40681), Granite 4.1 Vision (#40282), EXAONE-4.5 (#39388), BharatGen Param2MoE (#38000), Phi-4-reasoning-vision-15B (#38306), Cheers multimodal (#38788), telechat3 (#38510), FireRedLID (#39290), jina-reranker-v3 (#38800), Jina Embeddings v5 (#39575), Nemotron-v3 VL Nano/Super (#39747).
• Gemma4 series: fast prefill (#38879), quantized MoE (#39045), Eagle3 (#39450), block-local attention + YaRN for Gemma3 (#39823), bidirectional vision attention for sliding layers (#40534), token-repetition fix via dynamic BOS (#39842), multimodal embedder norm-order fix (#40411), plus a string of streaming/tool-call fixes (#38844, #38909, #38992, #39114, #39679, #39027).
• Quantization formats: GGUF support for MiniMax-M2.1 (#36965), non-standard GGUF quant types with prefix such as UD-IQ1_S (#39471).
• Speculative decoding: Eagle3 for MiniMax-M2 (#37512), Eagle3 for Gemma4 (#39450).
• LoRA: Qwen3ASRForConditionalGeneration (#37247), Gemma4ForConditionalGeneration (#39291, #38844), DeepSeek V3.2 (#35077), Qwen3.5 / Step3.x expert base_layer extension (#37114), MoE LoRA refactor (#40338), dual-CUDA-streams linear layer (#35721).
• Multimodal MRoPE refresh: mm_features-based MRoPE for Ernie-4.5 VL (#39753), Keye-VL / Keye-1.5-VL (#39869), PaddleOCR-VL (#39888).
• Other: Nano-Nemotron-VL static image inputs fix (#40724); Qwen3 MoE no longer calls gate twice (#40664); DeepSeek V2-Lite accuracy drop fix (#40673); Parakeet UX / perf enhancements (#39423); ColModernVBERT updated for latest HF checkpoint (#39307); NemotronH default mamba_ssm_cache_dtype=float32 with NemotronHNanoVLV2 auto-hook (#39032); new TP plan styles for the Transformers backend (#40467); GLM-5.1 fix on ROCm (#40763).

Engine Core

• Model Runner V2: Full CUDA graph for eagle prefill (#37588), auto cudagraph mode/sizes based on attention backend (#32936), fused probabilistic rejection-sample kernels (#38496), config validation (#38758), eagle-draft piecewise fallback disabled (#39773), multiple prompt logprobs (#39937), prefill warmup coverage (#40746), stale sampled/draft tokens accuracy fix (#39833).
• vLLM IR: IR skeleton + rms_norm (#33825), OOT kernel import hooks (#38807), gemma_rms_norm on IR (#39014), IR op testing/benchmarking infra (#40167).
• torch.compile: Opaque Objects on torch 2.11 (#39286), AOT compile with batch-invariance mode (#39201), Inductor cache nested under AOT dir (#39718), split FX graph via codegen (#38657), Inductor pre-grad passes re-enabled for torch≥2.12 (#38944), strings in custom ops without compile regressions (#38123), MLA + group FP8 fusion (#38877), SiluMul activation+quant fusion refactor (#39684), donate_graph_module=True for standalone_compile (#39733), skip FX graph deserialization on loading (#40151), include Inductor & functorch configs in compile-cache key (#40627), respect TORCH_COMPILE_DISABLE at vLLM config level (#40715), disable Sequence Parallelism for piecewise compilation (#38373).
• Attention: FA4 as default MLA prefill (#38819), head-dim 512 + paged-KV on sm90+FA4 (#38835), FA4 upstream sync (#38690), full CUDA graph for FlexAttention (#36298), FlexAttention non-causal support (#40394), unified 2D/3D triton_unified_attention (#40631), TRTLLM minimax_allreduce_rms ported (#37045), concat_mla_q half-types only (#37892), batch-invariance-aware backend auto-selection (#40193), avoid seq_lens_cpu GPU→CPU sync (#40654).
• Helion kernels: torch.compile support for Helion kernels (#38592).
• HMA / KV offload: GPU-side KV events for HMA (#37688), group block hashes/IDs tracked (#37109), unified memory layout for offloading workers (#37206), shutdown() on OffloadingConnector (#39182), request context passed through KV offload (#39185), sliding-window lookup (#36645), multi-group worker transfer (#38453), multi-KV-group lookup/load/store (#39401, #39402, #39403).
• Features: NUMA binding for GPU workers (#38635), opt-in VLLM_MEDIA_CACHE media URL caching (#37123), safe request abort when FSM fails to advance (#38663), KV connector prioritized over internal registry (#38301), CUDAGraph memory profiling on by default (#38284), shared-expert overlap restored (#39222), CONFIG_REGISTRY config-class lookup fix when on-disk model_type differs (#39554), workspace-resize GPU memory leak fix (#39226), SWA/chunked-local runtime admission capped to startup pool-sizing bound (#40946).
• Pluggable layers: Applied to llm_head / vocab embedding (#33465) and MoE layers (#33556).
• Mamba: Stochastic rounding (#35753), different Conv state layouts (#37416), FlashInfer selective_state_update (#36162).
• Metrics & scheduling: Labeled waiting-breakdown (capacity/deferred) metric (#38435), API server handshake simplified (#39364), mm-scheduler get_num_embed overhead reduced (#40143), request_id on FinishedRequestStats (#39710).
• Executor: RayExecutorV2 introduced (#36836); unified engine process monitoring with Ray backend (#35862).

Hardware & Performance

• NVIDIA: swapAB support for SM120 CUTLASS blockwise FP8 GEMM (#38325), MXFP4 W4A4 CUTLASS MoE for SM100 (#37463), TRTLLM GEN NVFP4 MoE with non-512-aligned hidden dims via weight padding (#39510), TRTLLM FP8 MoE with shuffled weights + BlockMajorK layout (#38993), fused qknorm+rope kernel on SM9.0 (#37376), tuned fused_moe config for RTX PRO 6000 Blackwell (#39183), ViT full CUDA graph for Qwen3-VL video (#38061), --enable-vit-cuda-graph for VLM examples (#40580), default max_frames_per_batch auto-infer for ViT CG video (#40445), fused FP8 output quantization into merge_attn_states (#36518), batched KV-cache swap via cuMemcpyBatchAsync (#38460), sm_110 (Jetson Thor) added to CUDA 13.0 build targets (#39233).
• AMD ROCm: ZenCPU / AMD Zen CPU backend via zentorch (#39967), RDNA 3.5/4 device IDs (gfx1150/1151/1201) (#38455), gfx1102/gfx1103 added (#40037), MORI EP for unquantized MoE with AITER (#37529), MoRI build with AMD AINIC stack (#38371), MoRI-IO message format aligned with P2pNcclConnector and vllm-router (#39565), MORI prefill/decode API correction (#39835), AITER gemm w8a8 ptpc integration (#33773), TritonW4...