README.md in tdlib-ruby-2.0.0 vs README.md in tdlib-ruby-2.1.0

- old
+ new

@@ -6,11 +6,11 @@
 
 Ruby bindings and client for TDLib (Telegram database library).
 
 ## Requirements
 
-* Ruby 2.3+
+* Ruby 2.4+
 * Compiled [tdlib](https://github.com/tdlib/td)
 
 We have precompiled versions for CentOS 6 & 7 in our repositories:
 
 http://rpms.southbridge.ru/rhel7/stable/x86_64/
@@ -27,10 +27,11 @@
 
 | Gem Version   |   | tdlib version |
 |:-------------:|:-:| :-----------: |
 | 1.x           | → | 1.0 - 1.2     |
 | 2.0           | → | 1.3           |
+| 2.1           | → | 1.5           |
 
 ## Install
 
 Add to your gemfile:
 
@@ -81,11 +82,11 @@
   loop do
     case state
     when :wait_phone_number
       puts 'Please, enter your phone number:'
       phone = STDIN.gets.strip
-      client.set_authentication_phone_number(phone).wait
+      client.set_authentication_phone_number(phone, nil).wait
     when :wait_code
       puts 'Please, enter code from SMS:'
       code = STDIN.gets.strip
       client.check_authentication_code(code).wait
     when :wait_password
@@ -151,9 +152,15 @@
 
 ```ruby
 TD::Client.new(database_directory: 'will override value from config',
                files_directory: 'will override value from config')
 ```
+
+If the tdlib schema changes, then `./bin/parse` can be run to
+synchronize the Ruby types with the new schema. Please look through
+`lib/tdlib/client_methods.rb` carefully, especially the set_password
+method!
+
 
 ## License
 
 [MIT](https://github.com/centosadmin/tdlib-ruby/blob/master/LICENSE.txt)
 