cmake 4.2.3 dropped support for cmake_minimum_required below 3.5
Author: bgemmillCreated Feb 26, 2026Updated Jul 22, 2026
I upgraded to cmake 4.2.3 from the kitware repository today to see about building on ubuntu 26.04 when it comes out, and it looks like cmake no longer supports cmake_minimum_required below 3.5.
When compiling libzmq with cmake, I get errors like:
CMake Error at CMakeLists.txt:7 (cmake_minimum_required):
Compatibility with CMake < 3.5 has been removed from CMake.
Update the VERSION argument <min> value. Or, use the <min>...<max> syntax
to tell CMake that the project requires at least <min> but has been updated
to work with policies introduced by <max> or earlier.
Or, add -DCMAKE_POLICY_VERSION_MINIMUM=3.5 to try configuring anyway.Can the supported version of cmake please be bumped up so this continues building?
Source: zeromq/libzmq