WordPress SEO was updated to version 1.4.18, from version 1.4.15. Changelog:
1.4.18
- Unhooking ‘shutdown’ (part of the NGG fix in 1.4.16) caused caching plugins to break, fixed while preserving NGG fix.
1.4.17
- Missed a line in the commit of the option to stop stop words cleaning.
1.4.16
- Fix for compatibility with NextGen Gallery.
- Add option to enable slug stop word cleaning, find it under SEO -> Permalinks. It’s on by default.
- Remove tracking variables from the Yoast Tracking that weren’t used.
- Updated de_DE, fa_IR, fi, hu_HU, it_IT, pl_PL, sv_SE and tr_TK