diff --git a/History.md b/History.md
index 6656b9b7..5ddf711d 100644
--- a/History.md
+++ b/History.md
@@ -1,3 +1,10 @@
+# Version 3.0.1
+Release date: unreleased
+
+### Changed
+
+* Restored ability for `Capybara.server=` to accept a proc which was accidentally removed in 3.0.0
+
 # Version 3.0.0
 Release date: 2018-04-05
 
diff --git a/lib/capybara/config.rb b/lib/capybara/config.rb
index 4043c0f5..4af9d197 100644
--- a/lib/capybara/config.rb
+++ b/lib/capybara/config.rb
@@ -53,7 +53,9 @@ module Capybara
     #
     def server=(name)
       name, options = *name if name.is_a? Array
-      @server = if options
+      @server = if name.respond_to? :call
+        name
+      elsif options
         proc { |app, port, host| Capybara.servers[name.to_sym].call(app, port, host, options) }
       else
         Capybara.servers[name.to_sym]
diff --git a/spec/capybara_spec.rb b/spec/capybara_spec.rb
index d37e693c..baf9ec3c 100644
--- a/spec/capybara_spec.rb
+++ b/spec/capybara_spec.rb
@@ -64,6 +64,18 @@ RSpec.describe Capybara do
     end
   end
 
+  describe "server=" do
+    after do
+      Capybara.server = :default
+    end
+
+    it "accepts a proc" do
+      server = ->(_app, _port) {}
+      Capybara.server = server
+      expect(Capybara.server).to eq server
+    end
+  end
+
   describe 'app_host' do
     after do
       Capybara.app_host = nil