diff --git a/poetry.lock b/poetry.lock
index ea6557b..06d1407 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -1,4 +1,4 @@
-# This file is automatically @generated by Poetry 1.6.1 and should not be changed by hand.
+# This file is automatically @generated by Poetry 1.7.1 and should not be changed by hand.
 
 [[package]]
 name = "black"
@@ -850,4 +850,4 @@ testing = ["big-O", "flake8 (<5)", "jaraco.functools", "jaraco.itertools", "more
 [metadata]
 lock-version = "2.0"
 python-versions = ">=3.7.0,<4"
-content-hash = "884e2836726c33f7f0706f663d1cbe5be4aef1d8431b3f7c5e345edd546a4095"
+content-hash = "96667100b25ee1687401451aff4febd96c69c83c39ba18422d707826894493db"
diff --git a/pyproject.toml b/pyproject.toml
index 27f5277..2c2ad0d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -15,7 +15,7 @@ packages = [
 python = ">=3.7.0,<4"
 requests = "^2.27.1"
 requests-futures = "^1.0.0"
-flagsmith-flag-engine = "^4.0.0"
+flagsmith-flag-engine = ">=4.0.0,<6"
 
 [tool.poetry.dev-dependencies]
 pytest = "^7.4.0"