The next version of JW Library for iPad/iPhone will require iOS 9, according to the release notes for version 9.1 of JW Library for iOS.
Version history:
Sep 2015: dropped support for iOS 6
May 2017: dropped support for iOS 7
later in 2017(?): dropping support for iOS 8
I think it's safe to say that one day an update will come that will drop support for iOS 9, meaning, those who have invested in their first iPad in order to use the latest 'digital' spiritual provisions will have to either:
1. pay money to buy new hardware (either a newer iPad, or, switching to Android by saving your notes backup file to google drive and manually restoring it to the android device)
2. continue to use the older version of JW Library, which may be able to receive new publications for a certain amount of time, but may eventually stop being able to update publications or download new ones
3. switch to ePub files / iBooks app, which supports basically all the reading functionalities of JW Library, but for audio and video, you could use a second app such as Documents by Readdle
If you want to go with option 3, it's probably not wise to rely on using JWL for permanent highlights or notes as there is currently no way to transfer these to iBooks. You may wish to use JWL for 'temporary' notes, such as those for an upcoming meeting, while keeping 'permanent' gems that you want to always have long term in multiple places; perhaps copying those out into rich text file that should be backwards compatible with nearly everything, probably as long as this system goes on for (and who knows, maybe after that also).