How to change the CSS version

Hello
I have a vanilla site , i also do some css update to change the theme.
so i come acorss problem
my theme modify from the default theme
and when i change the custom.css , my user`s explorer just cache the custom.css
the one slovtion is change the about.php`s version ,and the js or css request will append the theme version number ,so the explorer will get the new css file .
but i use the default , and the verson number is vanilla version number
i try to modify the vanilla version in config.php ,and it not work , i change the about.php version in default theme , and it not work too.
css also append 2.0.18.4
so ~~~ how can i do it ? any help
By the way , is there any update for html static , static the content not change.
0
Answers
@422 @x00 any help?
http://vanillaforums.org/discussion/19915/deploying-a-new-forum-and-adding-a-theme-for-everyone#Item_23
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thx for you attention , i found the problem , my about.php is broken , php syntax bug.