From c9a9df17f40c22301b4b6e4f2b555cc94eb00144 Mon Sep 17 00:00:00 2001 From: Jeremiah Lowin <153965+jlowin@users.noreply.github.com> Date: Sat, 10 Jan 2026 11:41:44 -0500 Subject: [PATCH] Add FastMCP 4.0 preview notice to installation guide (#2831) Co-authored-by: Claude --- docs/getting-started/installation.mdx | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/docs/getting-started/installation.mdx b/docs/getting-started/installation.mdx index edcaa5983..bde4b94a8 100644 --- a/docs/getting-started/installation.mdx +++ b/docs/getting-started/installation.mdx @@ -85,7 +85,19 @@ fastmcp==2.11.0 # Good fastmcp>=2.11.0 # Bad - will install breaking changes ``` -See the full [versioning and release policy](/development/releases#versioning-policy) for details on our public API, deprecation practices, and breaking change philosophy. +See the full [versioning and release policy](/development/releases#versioning-policy) for details on our public API, deprecation practices, and breaking change philosophy. + +### Looking Ahead: FastMCP 4.0 + +The MCP Python SDK v2 is expected in early 2026 and will include breaking changes. When released, FastMCP will incorporate these upstream changes in a new major version (FastMCP 4.0). + +To avoid unexpected breaking changes, we recommend pinning your dependency with an upper bound: + +``` +fastmcp>=3.0,<4 +``` + +We'll provide migration guidance when FastMCP 4.0 is released. ## Contributing to FastMCP