diff --git a/Gemfile.lock b/Gemfile.lock
index e8e5ee3..b21a7e5 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,8 +1,8 @@
 PATH
   remote: .
   specs:
-    simpol-jekyll-theme (1.0.4)
-      jekyll (~> 3.4)
+    simpol-jekyll-theme (1.0.5)
+      jekyll (>= 3.4, < 5.0)
       jekyll-feed (~> 0.9)
       jekyll-paginate (~> 1.1)
       jekyll-seo-tag (~> 2.2)
@@ -11,58 +11,72 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.5.2)
-      public_suffix (>= 2.0.2, < 4.0)
+    addressable (2.7.0)
+      public_suffix (>= 2.0.2, < 5.0)
     colorator (1.1.0)
-    ffi (1.9.18)
+    concurrent-ruby (1.1.5)
+    em-websocket (0.5.1)
+      eventmachine (>= 0.12.9)
+      http_parser.rb (~> 0.6.0)
+    eventmachine (1.2.7)
+    ffi (1.11.1)
     forwardable-extended (2.6.0)
-    jekyll (3.6.0)
+    http_parser.rb (0.6.0)
+    i18n (1.7.0)
+      concurrent-ruby (~> 1.0)
+    jekyll (4.0.0)
       addressable (~> 2.4)
       colorator (~> 1.0)
-      jekyll-sass-converter (~> 1.0)
-      jekyll-watch (~> 1.1)
-      kramdown (~> 1.14)
+      em-websocket (~> 0.5)
+      i18n (>= 0.9.5, < 2)
+      jekyll-sass-converter (~> 2.0)
+      jekyll-watch (~> 2.0)
+      kramdown (~> 2.1)
+      kramdown-parser-gfm (~> 1.0)
       liquid (~> 4.0)
       mercenary (~> 0.3.3)
       pathutil (~> 0.9)
-      rouge (>= 1.7, < 3)
+      rouge (~> 3.0)
       safe_yaml (~> 1.0)
-    jekyll-feed (0.9.2)
-      jekyll (~> 3.3)
+      terminal-table (~> 1.8)
+    jekyll-feed (0.12.1)
+      jekyll (>= 3.7, < 5.0)
     jekyll-paginate (1.1.0)
-    jekyll-sass-converter (1.5.0)
-      sass (~> 3.4)
-    jekyll-seo-tag (2.3.0)
-      jekyll (~> 3.3)
-    jekyll-sitemap (1.1.1)
-      jekyll (~> 3.3)
-    jekyll-watch (1.5.0)
-      listen (~> 3.0, < 3.1)
-    kramdown (1.15.0)
-    liquid (4.0.0)
-    listen (3.0.8)
-      rb-fsevent (~> 0.9, >= 0.9.4)
-      rb-inotify (~> 0.9, >= 0.9.7)
+    jekyll-sass-converter (2.0.1)
+      sassc (> 2.0.1, < 3.0)
+    jekyll-seo-tag (2.6.1)
+      jekyll (>= 3.3, < 5.0)
+    jekyll-sitemap (1.3.1)
+      jekyll (>= 3.7, < 5.0)
+    jekyll-watch (2.2.1)
+      listen (~> 3.0)
+    kramdown (2.1.0)
+    kramdown-parser-gfm (1.1.0)
+      kramdown (~> 2.0)
+    liquid (4.0.3)
+    listen (3.2.0)
+      rb-fsevent (~> 0.10, >= 0.10.3)
+      rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.3.6)
-    pathutil (0.16.0)
+    pathutil (0.16.2)
       forwardable-extended (~> 2.6)
-    public_suffix (3.0.0)
-    rb-fsevent (0.10.2)
-    rb-inotify (0.9.10)
-      ffi (>= 0.5.0, < 2)
-    rouge (2.2.1)
-    safe_yaml (1.0.4)
-    sass (3.5.2)
-      sass-listen (~> 4.0.0)
-    sass-listen (4.0.0)
-      rb-fsevent (~> 0.9, >= 0.9.4)
-      rb-inotify (~> 0.9, >= 0.9.7)
+    public_suffix (4.0.1)
+    rb-fsevent (0.10.3)
+    rb-inotify (0.10.0)
+      ffi (~> 1.0)
+    rouge (3.12.0)
+    safe_yaml (1.0.5)
+    sassc (2.2.1)
+      ffi (~> 1.9)
+    terminal-table (1.8.0)
+      unicode-display_width (~> 1.1, >= 1.1.1)
+    unicode-display_width (1.6.0)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  bundler (~> 1.14)
+  bundler (~> 1.16)
   simpol-jekyll-theme!
 
 BUNDLED WITH
diff --git a/simpol-jekyll-theme.gemspec b/simpol-jekyll-theme.gemspec
index 00e4a57..eef4716 100644
--- a/simpol-jekyll-theme.gemspec
+++ b/simpol-jekyll-theme.gemspec
@@ -13,7 +13,7 @@ Gem::Specification.new do |spec|
 
   spec.files         = `git ls-files -z`.split("\x0").select { |f| f.match(%r{^(assets|_layouts|_includes|_posts|LICENSE|README)}i) }
 
-  spec.add_runtime_dependency "jekyll", "~> 3.4"
+  spec.add_runtime_dependency "jekyll", ">= 3.4", "< 5.0"
   spec.add_runtime_dependency "jekyll-paginate", "~> 1.1"
   spec.add_runtime_dependency "jekyll-feed", "~> 0.9"
   spec.add_runtime_dependency "jekyll-sitemap", "~> 1.1"