Age Gate 3 is quite far into development (yay!) with general improvements across the board.
This is a major release and will have a considerable amount of breaking changes that should be addressed before upgrading. These fall in to core areas:
Hooks
The majority of actions and filters in Age Gate 3 will be different to those of Age Gate 2. Some filters have been replaced with actions where that is more appropriate, some may have been removed altogether and of course, loads have been added to make Age Gate even more customisable by developers that don’t mind getting their hands dirty.
Style
The CSS class structure follows BEM, which is a significant departure from that of version 2. If you have custom styles, there are two ways to keep things looking right; update your custom styles or continue using the old style via an option in the settings.
Key to these changes are the use of css variables to style Age Gate. This has made it easier to add custom styles quickly and easily. It has led to Admin users now having far more granular control over the appearance of Age Gate from the CMS, and better still, now in the Customiser so you can see what is happening in realtime.
In addition to these changes, the Javascript version now has far greater control within JS itself, with a substantial amount of hooks being able to be called straight from JS without needing extra Ajax calls or complex workarounds.
Full documentation on all the changes to follow.