README.md in daigaku-0.6.0 vs README.md in daigaku-1.0.0

- old
+ new

@@ -14,10 +14,10 @@
 language-explaining programming tasks.
 
 ## Installation
 
 First of all make sure Ruby is installed on your computer.
-Daigaku works with [MRI Ruby](https://www.ruby-lang.org/en/documentation/installation/) v2.4.5 or higher.
+Daigaku works with [MRI Ruby](https://www.ruby-lang.org/en/documentation/installation/) v2.5 or higher.
 
 Then open a terminal and install Daigaku by running:
 
     $ gem install daigaku
 