I installed 3.1.2. In the package the only style is prosilver.
Then I used the changed files to update form 3.1.2 to 3.1.3. In this package there is also a subsilver2 folder inside the styes folder. Only few files.
But there is not subsilver2 style in the original install (3.1.2) and, after the update, in the ACP there is the option to install (use) the subsilver style. And if I try to use it in a forum the forum is triggering an error (because I obviously dont' have the complete style installed).
Shouldn't the subsilver2 update be separate from the main phpBB update if it is not present in the main installation?