I've asked a review only to the sdrangel maintainers and not to all the dependencies' maintainers.

According to the CMake 4 tracking issue #445447, we should only set -DCMAKE_POLICY_VERSION_MINIMUM=3.5 in some very special cases, and prefer patching the packages in question instead. I already went through a bunch of the deps in question and submitted upstream fixes/backported upstream commits that didn't make it into a release yet, and it should be doable to also do so for the rest of the deps here.

Oh I missed that part, makes sense. I can do it for the remaining packages if you want. Do you suggest to open separate PRs for each package or do everything here in different commits?

In one PR is okay. Could you rebase on master in a few minutes (in around 3mins) to have all the changes

I swear I've read 3.5 😨, changed it now, good catch!

And patches are preferred over cmake flags, but I am fine with both.

Yeah I've read that but I think I had valid reasons to directly set the cmake flag from the derivation:

• aptdec's upstream repository is archived so I couldn't open a PR and use it as a patch
• using the latest dab_lib version it appears to already build against cmake 4, but bumping it made sdrangel to not build. dab_lib is used only by sdrangel in nixpkgs, so I believe that the optimal thing would be waiting for sdrangel to build against its latest version and then update it in nixpkgs (and remove my cmake flag)
• mbelib's upstream repository seems to be abandoned (last commit from 6 year ago) and unanswared PRs and issues. So here too I don't think it's worht opening a PR and using it in nixpkgs as patch.

For these 3 packages I may still write patches to put in nixpkgs or use substituteInPlace but honestly I preferred as I did. If someone with more authority and/or experience tells me to do differently, I will do differently.

nixpkgs-review result

Generated using nixpkgs-review.

Command: nixpkgs-review pr 449871
Commit: 697662f67a20b8b3af69a316a3ae5a751e562972

x86_64-linux

-- Detecting C compiler ABI info - done
-- Check for working C compiler: /nix/store/dmypp1h4ldn0vfk3fi6yfyf5yxp9yz0k-gcc-wrapper-14.3.0/bin/gcc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /nix/store/dmypp1h4ldn0vfk3fi6yfyf5yxp9yz0k-gcc-wrapper-14.3.0/bin/g++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
CMake Error at core/libcorrect/CMakeLists.txt:1 (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.
-- Configuring incomplete, errors occurred!

I agree. In some cases, including this one, a simple cmake flag makes more sense.

Versions older than <3.5 are unsupported by cmake 4. Versions between 3.5<=version<3.10 are deprecated and will lose support in a bit. The goal is to bump cmake compat version to at least 3.10+ so we won't have the same issues in half a year again.
If you are authoring patches, prefer bumping straight to 3.10.

So 3.5 wasn't wrong, 3.10 is just more future proof and recommended.

nixpkgs-review result

Generated using nixpkgs-review.

Command: nixpkgs-review pr 449871
Commit: 7d0808ab3845edb076f673c796798610e4ba2323

x86_64-linux

-- Detecting C compiler ABI info - done
-- Check for working C compiler: /nix/store/dmypp1h4ldn0vfk3fi6yfyf5yxp9yz0k-gcc-wrapper-14.3.0/bin/gcc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /nix/store/dmypp1h4ldn0vfk3fi6yfyf5yxp9yz0k-gcc-wrapper-14.3.0/bin/g++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
CMake Error at core/libcorrect/CMakeLists.txt:1 (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.
-- Configuring incomplete, errors occurred!

• For sdrpp: sdrpp: 1.1.0-unstable-2024-01-22 -> 1.2.1-unstable-2025-10-09 #450737