diff --git a/Project.toml b/Project.toml
index 6a215b8..11dd87c 100644
--- a/Project.toml
+++ b/Project.toml
@@ -23,19 +23,19 @@ Trapz = "592b5752-818d-11e9-1e9a-2b8ca4a44cd1"
 Zygote = "e88e6eb3-aa80-5325-afca-941959d7151f"
 
 [compat]
-Contour = "0.6"
+Contour = ">= 0.6"
 EFIT = ">= 0.1"
-ForwardDiff = "0.10"
+ForwardDiff = ">= 0.10"
 HCubature = "1"
 Interpolations = ">= 0.14.7"
 LRUCache = "1"
-Memoize = "0.4"
-NetCDF = "0.12"
+Memoize = ">= 0.4"
+NetCDF = ">= 0.12"
 Optim = "1"
-PolygonOps = "0.1"
+PolygonOps = ">= 0.1"
 StaticArrays = "1"
 Trapz = "2"
-Zygote = "0.6"
+Zygote = ">= 0.6"
 
 [extras]
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"