As far as I know it is like this:
InvoicePlane v1.x:
Created by @Kovah is IP1 as you maybe already know. So far so good.
Kevin is not longer maintaining this software (read THIS) so he searched a team of supporter/maintainer and now they are supporting this software.
InvoicePlane v2.0.0alpha-1:
This is basicaly FusionInvoice but just “moved” to InvoicePlane. I think not a log got changed as it really feels like it is FusionInvoice, at least I could not tell any differences.
I dont think so, never heard of announced releases.
I hope they will update IP2 to at least Laravel v4/v5 but this is up to the maintainers/developers.
I personally like CodeIgniter but I think Laravel/Symfony is much more up to date. Even when they seems to be much slower: SPEED-TEST.
Dont apologize for showing interest, this is the right place to asking, so everything is perfekt 