diff --git a/Project.toml b/Project.toml
index 8b9d043d..ac0ceaf6 100644
--- a/Project.toml
+++ b/Project.toml
@@ -28,7 +28,7 @@ Accessors = "0.1"
 ChainRulesCore = "1.0"
 Compat = "3.46, 4.2"
 FiniteDifferences = "0.12"
-KrylovKit = "0.8"
+KrylovKit = "0.8, 0.9"
 LinearAlgebra = "1"
 LoggingExtras = "1"
 MPSKit = "0.11"