diff --git a/Project.toml b/Project.toml
index 1202109..3411d2a 100644
--- a/Project.toml
+++ b/Project.toml
@@ -12,6 +12,9 @@ Libdl = "8f399da3-3557-5675-b5ff-fb832c97cbdb"
 Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
+[compat]
+FFTW = "1"
+
 [extras]
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"