--- a/propellor.cabal
+++ b/propellor.cabal
@@ -47,9 +47,10 @@ Library
     -- propellor needs to support the ghc shipped in Debian stable,
     -- and also only depends on packages in Debian stable.
     base >= 4.9, base < 5,
-    directory, filepath, IfElse, process, bytestring, hslogger, split,
-    unix, unix-compat, ansi-terminal, containers (>= 0.5), network, async,
-    time, mtl, transformers, exceptions (>= 0.6), stm, text, hashable
+    directory, filepath, IfElse, process, bytestring, hslogger,
+    split (>= 0.2.0.0), unix, unix-compat, ansi-terminal, containers (>= 0.5),
+    network, async (>= 2.0.0.0), time, mtl, transformers, exceptions (>= 0.6),
+    stm, text, hashable
   if flag(WithTypeErrors)
     Build-Depends: type-errors
     CPP-Options: -DWITH_TYPE_ERRORS

The added bounds prevent the following build errors:

src/System/Console/Concurrent/Internal.hs:28:1: error:
    Could not load module ‘Control.Concurrent.Async’
    It is a member of the hidden package ‘async-2.2.4’.
    Perhaps you need to add ‘async’ to the build-depends in your .cabal file.
    It is a member of the hidden package ‘async-2.2.4’.
    Perhaps you need to add ‘async’ to the build-depends in your .cabal file.
    it is a hidden module in the package ‘tasty-1.4.2.3’
    Use -v (or `:set -v` in ghci) to see a list of the files searched for.
   |
28 | import Control.Concurrent.Async
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
src/Propellor/Property/Dns.hs:29:44: error:
    Module ‘Data.List.Split’ does not export ‘chunksOf’
   |
29 | import qualified Data.List.Split as Split (chunksOf)
   |                                            ^^^^^^^^

done, thank you --Joey