Absolutely, we'll be supporting 2.5. Although the version number seems like a huge leap from 1.7, it can actually be considered to be 1.8, which means that it's not a huge change from the current Joomla version.
When 1.7 was released, we had already done our testing and supported it from day 1. We've done some preliminary testing with 2.5 and run into no real issues, and will definitely be supporting 2.5 as soon as it's available. If necessary, we'd quickly release an update to JFBConnect to fix any compatibility issues if any are found.
Hope that helps,
Alex