diff --git a/.ruby-version b/.ruby-version
index 5154b3f..1effb00 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-2.6
+2.7
diff --git a/.travis.yml b/.travis.yml
index 1788908..3b4448f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,12 +3,12 @@ sudo: false
 matrix:
   include:
     - rvm: jruby-9.2.9.0
-    - rvm: 2.4.9
     - rvm: 2.5.7
     - rvm: 2.6.5
     - rvm: jruby-head
     - rvm: ruby-head
-    - rvm: 2.6.5
+    - rvm: 2.7.1
+    - rvm: 2.7.1
       install: true # This skips 'bundle install'
       script: gem build *.gemspec && gem install *.gem
   allow_failures:
diff --git a/twingly-url.gemspec b/twingly-url.gemspec
index 774d3b6..a1bbf28 100644
--- a/twingly-url.gemspec
+++ b/twingly-url.gemspec
@@ -12,10 +12,10 @@ Gem::Specification.new do |s|
   s.summary     = "Ruby library for URL handling"
   s.description = "Twingly URL tools"
   s.license     = "MIT"
-  s.required_ruby_version = "~> 2.4"
+  s.required_ruby_version = "~> 2.5"
 
   s.add_dependency "addressable", "~> 2.6"
-  s.add_dependency "public_suffix", "~> 3.0.1"
+  s.add_dependency "public_suffix", ">= 3.0.1", "< 5.0"
 
   s.add_development_dependency "rake", "~> 12"
   s.add_development_dependency "rspec", "~> 3"