Google announced on Google+ that they will now automatically convert eligible Flash ads to HTML5 format, this way the ad can be displayed on more devices.
Google said they are "introducing a way to automatically convert Flash ads to HTML5, giving advertisers better access to the portion of Google Display Network inventory that is HTML5-only."
How do you know if your Flash ad is eligible? You can use Google's Swiffy tool and if that tool converts your Flash ad then Google will auto-convert your Flash ads.
Google explains in their help center:
Not all Flash ads can be converted to HTML5. To see whether your Flash ad will convert, upload it to the Swiffy tool. If this tool is able to convert your ad, then your ad will be automatically converted when it is uploaded to AdWords.To see in your AdWords reports whether your Flash ad was converted, segment your ad table by devices. If you see mobile or tablet impressions for a Flash ad, then your ad was converted.
In the future, we will be providing a notification on all converted Flash ads. We expect this to be available in late 2015.
Forum discussion at Google+ & WebmasterWorld.
