diff --git a/ttfunk.gemspec b/ttfunk.gemspec
index 9ee442c..118a4fc 100644
--- a/ttfunk.gemspec
+++ b/ttfunk.gemspec
@@ -50,6 +50,6 @@ Gem::Specification.new do |spec|
   }
 
   spec.required_ruby_version = '>= 2.7'
-  spec.add_runtime_dependency('bigdecimal', '~> 3.1')
+  spec.add_runtime_dependency('bigdecimal', '>= 3.1')
   spec.add_development_dependency('prawn-dev', '~> 0.4.0')
 end