On February 25, 2015, Google Adwords announced in there Google+ post that now all eligible Flash ads will automatically converted into HTML5. This will enable the flash ads to be displayed on more devices.
Access more inventory with Flash to HTML5 auto conversion. Read more: http://t.co/z45cRj0iol
— Google AdWords (@adwords) February 25, 2015
Google said that they are trying to improve advertising experience by automatically converting flash ads to HTML5. This will help the advertisers to better access the portion of Google Display Network inventory that is HTML5-only.
If you are any advertiser and if you want to know if your flash ad is eligible or not, you can cross check it using Google Swiffy tool. If that tool converts your flash ads to HTML5 then Google will surely auto-convert your flash ads.
You can get more details of this announcement at Google help center.
A small snippet of the announcement from 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.