diff --git a/Project.toml b/Project.toml
index 576bd7a4..b4e94733 100644
--- a/Project.toml
+++ b/Project.toml
@@ -46,7 +46,7 @@ Bessels = "0.2"
 DataStructures = "0.18 - 0.19"
 ElementaryPDESolutions = "0.2 - 0.3"
 FMM2D = "0.2"
-FMM3D = "1"
+FMM3D = "1, 2"
 FMMLIB2D = "0.3"
 ForwardDiff = "0.10, 1"
 Gmsh = "0.3"