diff --git a/Project.toml b/Project.toml
index 971c2f1a..693063d0 100755
--- a/Project.toml
+++ b/Project.toml
@@ -58,7 +58,7 @@ LowRankApprox = "0.5.5"
 MPI = "0.20.23"
 PartitionedArrays = "0.3"
 Plots = "1.40"
-RadialBasisFunctions = "0.2"
+RadialBasisFunctions = "0.2, 0.4"
 Revise = "3.13"
 SparseMatricesCSR = "0.6"
 StaticArrays = "1"