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Werk #22277: Plug-in APIs: the unstable API versions of 2.5 are now stable

Component Checks & agents
Title Plug-in APIs: the unstable API versions of 2.5 are now stable
Date Sep 18, 2026
Level Trivial Change
Class New Feature
Compatibility Compatible - no manual interaction needed
Checkmk versions & editions
3.0.0b1
Not yet released 		Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT

The plug-in APIs that Checkmk 2.5 shipped as "unstable" are declared stable with Checkmk 3.0. Their code now lives in the plain versioned namespace:

  • cmk.bakery.v2_unstable is now cmk.bakery.v2
  • cmk.inventory_ui.v1_unstable is now cmk.inventory_ui.v1
  • cmk.password_store.v1_unstable is now cmk.password_store.v1
  • cmk.server_side_programs.v1_unstable is now cmk.server_side_programs.v1

You do not have to change anything right now. The old *_unstable namespaces keep working as aliases: they expose exactly the same objects, so existing plug-ins continue to run unmodified.

However, the *_unstable aliases will be removed in Checkmk 3.1. Please migrate your plug-ins before then. Migrating means replacing the module path in your imports, for instance

from cmk.bakery.v2_unstable import BakeryPlugin

becomes

from cmk.bakery.v2 import BakeryPlugin

Note that Checkmk 3.0 is not released yet. Until it is released, these APIs may still change. The stability guarantee takes effect with the 3.0 release.

The API versions cmk.agent_based.v3_unstable and cmk.graphing.v2_unstable are not affected by this werk. They were never part of a release and remain unstable.

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