diff --git a/Project.toml b/Project.toml
index ff3e9bc5..878f7b06 100644
--- a/Project.toml
+++ b/Project.toml
@@ -45,7 +45,7 @@ DocStringExtensions = "0.8, 0.9"
 Enzyme = "0.13"
 FillArrays = "1.3"
 ForwardDiff = "0.10"
-Functors = "0.4"
+Functors = "0.4, 0.5"
 LinearAlgebra = "1"
 LogDensityProblems = "2"
 Mooncake = "0.4"