diff --git a/README.md b/README.md
index b5092f1..2093694 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,6 @@ Just use the `pavpanchekha/setup-z3` action. It has three inputs:
 
 - `version`: a version number for Z3; **required**.
 - `architecture`: `x64` by default, can be set to `x86` for the Windows build.
-- `distribution`: `ubuntu-18.04` by default; find other options [here][z3-releases].
+- `distribution`: `glibc-2.31` by default for use on `ubuntu`; find other options [here][z3-releases].
 
 [z3-releases]: https://github.com/Z3Prover/z3/releases