diff --git a/saas/fizzy-saas.gemspec b/saas/fizzy-saas.gemspec
index 6acc1bda2..7f993fbfd 100644
--- a/saas/fizzy-saas.gemspec
+++ b/saas/fizzy-saas.gemspec
@@ -34,5 +34,5 @@ Gem::Specification.new do |spec|
   spec.add_dependency "yabeda-prometheus-mmap"
   spec.add_dependency "yabeda-puma-plugin"
   spec.add_dependency "yabeda-rails", ">= 0.10"
-  spec.add_dependency "prometheus-client-mmap"
+  spec.add_dependency "prometheus-client-mmap", "~> 1.4.0"
 end