diff --git a/Project.toml b/Project.toml
index 60391f9..c4029ec 100644
--- a/Project.toml
+++ b/Project.toml
@@ -10,7 +10,7 @@ Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 Unitful = "1986cc42-f94f-5a68-af5c-568840ba703d"
 
 [compat]
-AtomsBase = "0.3"
+AtomsBase = "0.3, 0.4"
 StaticArrays = "1"
 Test = "1"
 Unitful = "1"
diff --git a/src/AtomsCalculators.jl b/src/AtomsCalculators.jl
index 0c95c5c..3e07bce 100644
--- a/src/AtomsCalculators.jl
+++ b/src/AtomsCalculators.jl
@@ -1,7 +1,7 @@
 module AtomsCalculators
 
 
-using AtomsBase
+using AtomsBase: AbstractSystem
 using StaticArrays
 using Unitful