I have migrated some site collections from a SP2010 farm to SP2013 farm. I have fully upgraded a site to SP2013 mode. In the Master file I have code like below:
<SharePoint:CssRegistration name="/_layouts/mycompany/develop/styles/style.css" runat="server" after="SharepointCssFile"/>
By some reason, above line actually refer to \Microsoft Shared\Web Server Extensions\14\TEMPLATE\LAYOUTS\ not \Microsoft Shared\Web Server Extensions\15\TEMPLATE\LAYOUTS\
I have tried modified to:
<SharePoint:CssRegistration name="/15/_layouts/mycompany/develop/styles/style.css" runat="server" after="SharepointCssFile"/>
But it still refer to \14\ path. I have tested remove the \14\ path css files and all style will be gone.
Although I can work on the style sheets (CSS files) at \14\ path, I am worrying it will cause some conflict in future. Are there some configure I overlook? Please share your experience. Thank you!