Apple drops Microsoft's Bing in favor of Google for Siri web search results on iOS
Switching to Google as the web search provider for Siri, Search within iOS and Spotlight on Mac will allow these services to have a consistent web search experience with the default in Safari. We have strong relationships with Google and Microsoft and remain committed to delivering the best user experience possible, reads Apple's press statement.
In the same piece of news, Apple announced that Spotlight on Mac will also use Google's search instead of Bing going forward, so there's that.
Apple stated that the changes announced today have been made to “allow these services to have a consistent web search experience with the default in Safari,” and has nothing to do with the relationships with Google and Microsoft.
source: TechCrunch
Things that are NOT allowed: