From e6f710a87f3ce8b137d15ffa4b3a12568e1c8aa3 Mon Sep 17 00:00:00 2001
From: Harry Mellor <19981378+hmellor@users.noreply.github.com>
Date: Mon, 27 Apr 2026 16:19:57 +0100
Subject: [PATCH] Deprecate support for Transformers v4 (#40389)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
---
 vllm/transformers_utils/config.py | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/vllm/transformers_utils/config.py b/vllm/transformers_utils/config.py
index 32241aec53e..bb6ad1056b7 100644
--- a/vllm/transformers_utils/config.py
+++ b/vllm/transformers_utils/config.py
@@ -66,6 +66,13 @@ MISTRAL_CONFIG_NAME = "params.json"
 
 logger = init_logger(__name__)
 
+if Version(version("transformers")) < Version("5.0.0"):
+    logger.warning(
+        "Support for Transformers v4 is deprecated. The Transformers v4 codepath will "
+        "become unmaintained in vLLM v0.22.0 and will be removed in vLLM v0.24.0. "
+        "Please upgrade to Transformers v5: pip install --upgrade transformers"
+    )
+
 
 class LazyConfigDict(dict):
     def __getitem__(self, key):