diff --git a/Project.toml b/Project.toml
index 81cb3a70..e5e0d509 100644
--- a/Project.toml
+++ b/Project.toml
@@ -45,7 +45,7 @@ Combinatorics = "0.7, 1"
 CompScienceMeshes = "0.10"
 Compat = "2, 3, 4"
 ConvolutionOperators = "0.4"
-ExtendableSparse = "1.4"
+ExtendableSparse = "1.4, 2"
 FFTW = "0.2.3, 1"
 FastGaussQuadrature = "0.3, 0.4, 0.5, 1"
 FillArrays = "0.11, 0.12, 0.13, 1"