Change Details

So that we don't have to maintain too much compatibility... [] Make extensions installable with 9.0 only [] Wikibase [] WikibaseLexeme [x] WikibaseQuality (This is no longer deployed) [] [WikibaseQualityConstraints](https://gerrit.wikimedia.org/r/472024) [] PropertySuggester [] WikibaseMediaInfo

So that we don't have to maintain too much compatibility... [x] Make extensions installable with 9.0 only [x] Wikibase [x] WikibaseLexeme [x] WikibaseQuality (This is no longer deployed) [x] [WikibaseQualityConstraints](https://gerrit.wikimedia.org/r/472024) [x] PropertySuggester [x] WikibaseMediaInfo

So that we don't have to maintain too much compatibility... [x] Make extensions installable with 9.0 only [x] Wikibase [x] WikibaseLexeme [x] WikibaseQuality (This is no longer deployed) [x] [WikibaseQualityConstraints](https://gerrit.wikimedia.org/r/472024) [x] PropertySuggester [x] WikibaseMediaInfo