Werk #18119: Fix tag drop-down with a single choice

Component

Setup

Title

Fix tag drop-down with a single choice

Date

Jun 4, 2025

Level

Trivial Change

Class

Bug Fix

Compatibility

Incompatible - Manual interaction might be required

Checkmk versions & editions

2.5.0b1 Not yet released	Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Ultimate MT
2.4.0p5	Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Ultimate MT
2.3.0p35	Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Ultimate MT

After the changes made in Werk #17836, some additional legacy code needed to be removed to support tag options when there is only one choice available.

This may have created rules with the null value set, which is not supported anymore. Therefore, running cmk-update-config is needed to run post update. This will remove the null tag from existing rules.

To the list of all Werks