(Or whatever the latest (very end of 2018) snapshot is)
I'd like to share with you my experimental results.
I have world, on which I am since the beginning. I've built a lot of there and I want to continue in newer versions. I'm on 1.12.2, with forge and some mods, not many. I am kind of dependent on those mods.
So, naturally, I've created copy of my world for experiments. And before anything, I've tried to delete forges stuff from NTB. Except…it's impossible. It has it's signature in EVERY. SINGLE. CHUNK. So I've removed everything but that. I don't have million years and tools for mass find and delete (aka replace with nothing) does not seem to exist. Whatever.
At this point, I had it ready. No blocks or items from mods, nothing. Just ready to be played on vanilla MC. And I did that. On 1.12.2. Just because I wanted vanilla 1.12.2 to be the last one doing anything. So far, so good.
Then, I fired up 1.13.2. Loaded my world. Waited about 1 minute, crash. Not surprising. Tried to optimize world (restored from backup, because if 1.13.2 crashes with some world, that one is just done). Error. That's it. No explanation. Cool.
Restored from backup, fired up 1.13. Loaded world. Everything OK. And kill EVERYTHING. Just to be sure. About 2000 animals. Oh, well. Now, backup. Fire up 1.13.2, and it works. Again. I'm not surprised. Cool. Backup, fire up latest snapshot, whatever it is, and…it works. Except some things. Parts of my builds were just…overwritten by terrain. No, those chinks were not deleted. Because if they would, I wouldn't be able to see remnants of my structures.
I've tested couple of other things, one resulted in just…destroyed world in latest snapshot. Specifically, no new chunk loading. So I was just stuck.
I am interested to know your experiences with this. From moded 1.12.2 world to 1.13.2 or newer. Was it smooth?