A lot of BlueSpice extensions have an extension.json in REL1_27 that claims to be version 2. That is not available in REL1_27!
```
BlueSpiceAbout/extension.json: unsupported manifest_version: 2
BlueSpiceArticleInfo/extension.json: unsupported manifest_version: 2
BlueSpiceAuthors/extension.json: unsupported manifest_version: 2
BlueSpiceAvatars/extension.json: unsupported manifest_version: 2
BlueSpiceBlog/extension.json: unsupported manifest_version: 2
BlueSpiceChecklist/extension.json: unsupported manifest_version: 2
BlueSpiceConfigManager/extension.json: unsupported manifest_version: 2
BlueSpiceDashboards/extension.json: unsupported manifest_version: 2
BlueSpiceExtendedStatistics/extension.json: unsupported manifest_version: 2
BlueSpiceGroupManager/extension.json: unsupported manifest_version: 2
BlueSpiceInsertCategory/extension.json: unsupported manifest_version: 2
BlueSpiceInsertLink/extension.json: unsupported manifest_version: 2
BlueSpiceInsertMagic/extension.json: unsupported manifest_version: 2
BlueSpiceInterWikiLinks/extension.json: unsupported manifest_version: 2
BlueSpiceNamespaceCSS/extension.json: unsupported manifest_version: 2
BlueSpiceNamespaceManager/extension.json: unsupported manifest_version: 2
BlueSpicePageAccess/extension.json: unsupported manifest_version: 2
BlueSpicePageAssignments/extension.json: unsupported manifest_version: 2
BlueSpicePageTemplates/extension.json: unsupported manifest_version: 2
BlueSpicePermissionManager/extension.json: unsupported manifest_version: 2
BlueSpiceReaders/extension.json: unsupported manifest_version: 2
BlueSpiceRSSFeeder/extension.json: unsupported manifest_version: 2
BlueSpiceSmartlist/extension.json: unsupported manifest_version: 2
BlueSpiceSmartList/extension.json: unsupported manifest_version: 2
BlueSpiceUEModulePDF/extension.json: unsupported manifest_version: 2
BlueSpiceUniversalExport/extension.json: unsupported manifest_version: 2
BlueSpiceWhoIsOnline/extension.json: unsupported manifest_version: 2
```