diff --git a/ProMotion-map.gemspec b/ProMotion-map.gemspec
index 696a537..74c917b 100644
--- a/ProMotion-map.gemspec
+++ b/ProMotion-map.gemspec
@@ -16,7 +16,7 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(%r{^(spec)/})
   spec.require_paths = ["lib"]
 
-  spec.add_dependency "ProMotion", "~> 2.0.0"
+  spec.add_dependency "ProMotion", "~> 2.0.0.rc4"
   spec.add_development_dependency "motion-stump", "~> 0.3"
   spec.add_development_dependency "motion-redgreen", "~> 0.1"
   spec.add_development_dependency "rake"