diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index b43fbbab..eb396bff 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -21,14 +21,13 @@ jobs:
         - 'pypy-3.10'
         # this version range needs to be synchronized with the one in pyproject.toml
         amaranth-version:
-        - '0.4'
         - '0.5'
         - 'git'
         allow-failure:
         - true
         - false
         exclude: # all of these are inverted (this is unfortunately the best way to do this)
-        - amaranth-version: '0.4'
+        - amaranth-version: '0.5'
           allow-failure: false
         - amaranth-version: 'git'
           allow-failure: true
diff --git a/pyproject.toml b/pyproject.toml
index 1882d756..46a389db 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -14,7 +14,7 @@ license = {file = "LICENSE.txt"}
 requires-python = "~=3.9"
 dependencies = [
   # this version requirement needs to be synchronized with the one in .github/workflows/main.yml
-  "amaranth>=0.4,<0.7",
+  "amaranth>=0.5,<0.7",
 ]
 
 [project.urls]