Till now we have been maintaining both Bootstrap 2 & Bootstrap 3 layouts for all extensions. However this is taking a toll on the release cycle and changes have to be done in both the layouts.
Over time we have seen that very few customers are using Bootstrap 2 templates now so this decision seems logical to take. However we have always maintained that we will maintain Bootstrap2 support till the Joomla core maintains it and we wanted to be double sure before taking this decision.
So we reached out to various popular template clubs both over the internet and at conferences we attend, the latest being at JWC Vancouver to get their feedback. Template clubs typically have a much larger user base and typically know more of what the masses are using. The feedback there too was that the users using Bootstrap 2 are very less and they too are seem to be migrating to Bootstrap 3. Post this, we decided that the time had come to stop supporting Bootstrap 2.