diff --git a/configs/sl15.5.conf b/configs/sl15.5.conf
index 794da5976..87f250558 100644
--- a/configs/sl15.5.conf
+++ b/configs/sl15.5.conf
@@ -454,6 +454,8 @@ Prefer: wine-32bit wine-devel-32bit wine-devel
 # have choice for pkgconfig(nunit): nunit-devel nunit3-devel; as usual, unversioned one wins
 Prefer: -nunit3-devel
 
+Prefer: -libz-ng-compat1
+
 # 32bit -devel packages contain .pc files and cause a 'have choice' for OBS. unfavor the -32bit variants
 Prefer: -ColPack-devel-32bit                          
 Prefer: -FAudio-devel-32bit