**Setup**
- MediaWiki 1.27.1 (a52d35d)
- PHP 5.6.27-0+deb8u1 (apache2handler)
- MariaDB 10.0.28-MariaDB-1~jessie
- Page Forms 4.0 (65049e9)
**Description**
When trying to invoke the extension with `wfLoadExtension( 'PageForms' );` the wiki fatals with:
**Backtrace**
```
PHP Fatal error: Uncaught exception 'Exception' with message '/.../w/extensions/PageForms/extension.json: unsupported manifest_version: 2' in /../w/includes/registration/ExtensionRegistry.php:195
Stack trace:
#0 /.../w/includes/registration/ExtensionRegistry.php(137): ExtensionRegistry->readFromQueue(Array)
#1 /.../w/includes/Setup.php(39): ExtensionRegistry->loadFromQueue()
#2 /.../w/maintenance/doMaintenance.php(97): require_once('/var/www/htdocs...')
#3 /.../w/maintenance/runJobs.php(127): require_once('/var/www/htdocs...')
#4 {main}
thrown in /.../w/includes/registration/ExtensionRegistry.php on line 195
```
My idea was to mitigate by changing the manifest version in the "extension.json" file to 1. This is probably the way to go but then I run into an issue with the Semantic Title extension:
```
[19fc9ffb5921c178db377c0a] /wiki/Main_Page MWException from line 176 of /.../w/includes/Hooks.php: Invalid callback PFHooks::initProperties in hooks for smwInitProperties
**Backtrace***
#0 /.../w/extensions/SemanticMediaWiki/src/PropertyRegistry.php(491): Hooks::run(string)
#1 /.../w/extensions/SemanticMediaWiki/src/PropertyRegistry.php(81): SMW\PropertyRegistry->registerPredefinedProperties(boolean)
#2 /.../w/extensions/SemanticMediaWiki/includes/dataitems/SMW_DI_Property.php(468): SMW\PropertyRegistry::getInstance()
#3 /.../w/extensions/SemanticMediaWiki/src/SQLStore/PropertyTableDefinitionBuilder.php(159): SMW\DIProperty::getPredefinedPropertyTypeId(string)
#4 /.../w/extensions/SemanticMediaWiki/src/SQLStore/PropertyTableDefinitionBuilder.php(57): SMW\SQLStore\PropertyTableDefinitionBuilder->addTableDefinitionForFixedProperties(array, string)
#5 /.../w/extensions/SemanticMediaWiki/src/SQLStore/PropertyTableInfoFetcher.php(220): SMW\SQLStore\PropertyTableDefinitionBuilder->doBuild()
#6 /.../w/extensions/SemanticMediaWiki/src/SQLStore/PropertyTableInfoFetcher.php(189): SMW\SQLStore\PropertyTableInfoFetcher->buildDefinitionsForPropertyTables()
#7 /.../w/extensions/SemanticMediaWiki/includes/storage/SQLStore/SMW_SQLStore3.php(592): SMW\SQLStore\PropertyTableInfoFetcher->getPropertyTableDefinitions()
#8 /.../w/extensions/SemanticMediaWiki/includes/storage/SQLStore/SMW_SQLStore3_Readers.php(81): SMWSQLStore3->getPropertyTables()
#9 /.../w/extensions/SemanticMediaWiki/src/SQLStore/EntityStore/DirectEntityLookup.php(42): SMWSQLStore3Readers->getSemanticData(SMW\DIWikiPage, boolean)
#10 /.../w/extensions/SemanticMediaWiki/src/SQLStore/EntityStore/PersistentCachedEntityLookup.php(110): SMW\SQLStore\EntityStore\DirectEntityLookup->getSemanticData(SMW\DIWikiPage, boolean)
#11 /.../w/extensions/SemanticMediaWiki/includes/storage/SQLStore/SMW_SQLStore3.php(202): SMW\SQLStore\EntityStore\PersistentCachedEntityLookup->getSemanticData(SMW\DIWikiPage, boolean)
#12 /.../w/extensions/SemanticTitle/SemanticTitle.class.php(413): SMWSQLStore3->getSemanticData(SMW\DIWikiPage)
#13 /.../w/extensions/SemanticTitle/SemanticTitle.class.php(269): SemanticTitle::getSemanticTitle(Title, NULL)
#14 [internal function]: SemanticTitle::onParserBeforeStrip(Parser, string, StripState)
#15 /.../w/includes/Hooks.php(195): call_user_func_array(string, array)
#16 /.../w/includes/parser/Parser.php(653): Hooks::run(string, array)
#17 /.../w/includes/parser/Parser.php(5101): Parser->preprocess(string, Title, ParserOptions)
#18 /.../w/includes/cache/MessageCache.php(1036): Parser->transformMsg(string, ParserOptions, Title)
#19 /.../w/includes/Message.php(1162): MessageCache->transform(string, boolean, Language, Title)
#20 /.../w/includes/Message.php(829): Message->transformText(string)
#21 /.../w/includes/Message.php(892): Message->toString()
#22 /.../w/includes/OutputPage.php(927): Message->text()
#23 /.../w/includes/OutputPage.php(975): OutputPage->setHTMLTitle(Message)
#24 /.../w/includes/page/Article.php(504): OutputPage->setPageTitle(string)
#25 /.../w/includes/actions/ViewAction.php(44): Article->view()
#26 /.../w/includes/MediaWiki.php(503): ViewAction->show()
#27 /.../w/includes/MediaWiki.php(288): MediaWiki->performAction(Article, Title)
#28 /.../w/includes/MediaWiki.php(745): MediaWiki->performRequest()
#29 /.../w/includes/MediaWiki.php(519): MediaWiki->main()
#30 /.../w/index.php(43): MediaWiki->run()
#31 {main}
```
Thus also pinging @cicalese