diff --git a/changelog.d/396.misc b/changelog.d/396.misc
new file mode 100644
index 00000000..0c1aa80d
--- /dev/null
+++ b/changelog.d/396.misc
@@ -0,0 +1 @@
+Pin `aiohttp` dependency to <= 4.0.0.
\ No newline at end of file
diff --git a/pyproject.toml b/pyproject.toml
index f1604b44..c368b295 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -71,7 +71,7 @@ include = [
 [tool.poetry.dependencies]
 python = "^3.8.0"
 aioapns = ">=3.0"
-aiohttp = ">=3.8.0"
+aiohttp = "^3.8.0"
 attrs = ">=19.2.0"
 cryptography = ">=2.6.1"
 idna = ">=2.8"