diff --git a/pyproject.toml b/pyproject.toml
index 301fd487..2f328bd5 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -18,7 +18,7 @@ dependencies = [
   "black>=26,<27",                       # needed for bw-generate-cli
   "copier~=9.7",
   "darkdetect~=0.8",
-  "isort>=5.13, <9.0",                   # needed for bw-generate-cli
+  "isort>=5.13, <10.0",                   # needed for bw-generate-cli
   "markdown~=3.9",
   "ophyd_devices~=1.29, >=1.29.1",
   "pydantic~=2.0",