diff --git a/Project.toml b/Project.toml
index 53364762..0f7960ec 100644
--- a/Project.toml
+++ b/Project.toml
@@ -44,7 +44,7 @@ WriteVTK = "64499a7a-5c06-52f2-abe2-ccb03c286192"
 Arpack = "0.5"
 BenchmarkTools = "1"
 DiffEqCallbacks = "2"
-Documenter = "0.27"
+Documenter = "0.27, 1"
 DocumenterTools = "0.1"
 GFlops = "0.1.7"
 GR = "0.72"