This package either build-depends on libboost-system-dev or depends on it.

The boost system library was removed upstream in 1.89, and is empty since 1.69.
If this library is referenced in the build system, the library can just be
removed from the build system, and the package should continue to build
for any boost version newer than 1.69, including boost1.83 in Debian.

There is no need to wait until boost 1.90 becomes the default, the issue
can be addressed in unstable. Issues to check:

  - Remove libboost-system-dev in Depends and Build-Depends.

  - Adjust autopkg tests and test dependencies if needed.

  - Scan the build system if the library is used, and remove it
    from the build system. https://www.boost.org/releases/1.89.0/
    has a short paragraph how to do that for cmake.

boost1.90 is now available in unstable, and a boost-defaults
defaulting to 1.90 is available in experimental. Please also check
that the package builds with boost 1.90.

Hello,

Bug #1127186 in cufflinks reported by you has been fixed in the
Git repository and is awaiting an upload. You can see the commit
message below and you can check the diff of the fix at:

https://salsa.debian.org/med-team/cufflinks/-/commit/c0672a03dcb9507d3185901e16131cb0c4a0ae28

(this message was generated automatically)
-- 
Greetings

https://bugs.debian.org/1127186