After upgrading to 2.4.0, I get this error:

./propellor --spin myserver
Building propellor-2.4.0...
Preprocessing library propellor-2.4.0...
In-place registering propellor-2.4.0...
Preprocessing executable 'propellor' for propellor-2.4.0...
Preprocessing executable 'propellor-config' for propellor-2.4.0...
Propellor build ... done
Git commit ... done
Enter passphrase for /home/user/.ssh/id_rsa: 
Identity added: /home/user/.ssh/id_rsa (/home/user/.ssh/id_rsa)
Counting objects: 253, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (253/253), done.
Writing objects: 100% (253/253), 173.59 KiB | 0 bytes/s, done.
Total 253 (delta 172), reused 0 (delta 0)
To root@myserver:/var/lib/git/private/propellor.git
   d81fb7d..6f7f041  master -> master
Push to central git repository ... done
From myserver:/var/lib/git/private/propellor
   d81fb7d..6f7f041  master     -> origin/master
Pull from central git repository ... done
** warning: git branch origin/master is not signed with a trusted gpg key; refusing to deploy it! (Running with previous configuration instead.)
Sending privdata (87652 bytes) to myserver ... done
From .
 * branch            HEAD       -> FETCH_HEAD
Sending git update to myserver ... done
Warning: The package list for 'hackage.haskell.org' is 47 days old.
Run 'cabal update' to get the latest list of available packages.
Resolving dependencies...
Configuring propellor-2.4.0...
cabal: At least the following dependencies are missing:
exceptions -any
propellor: failed to make dist/setup-config
Shared connection to myserver closed.
propellor: remote propellor failed

As in https://propellor.branchable.com/todo/issue_after_upgrading_shared_library/, manually running "make clean" on the server fixed the issue

Ok, this is the same as problem with spin after new dependencies added. Closing this issue as I'm dealing with it in the other one. done --Joey