We have so many bug fixes for you it is hard to list them all, from ones many people reported like Juggler Irwin on Route 35 causing a crash and the "ceruleandiglett" missing script; to battle problems, like the game softlocking when doing some animations, or multi turn moves like Rollout behaving weird when switched; to typos and code inconsistencies.
While there are a ton of bug fixes dont let the new features get drowned out either; moves and Pokémon have been updated with Gen 9 mechanics, a new model hinting at future content on Route 50, Destiny Knot is now available (with breeding mechanics too), Item names, descriptions, and categories can now be localized, Poison will now damage pokemon while walking around at higher difficulties, and TMs wont break at higher difficulties.
The biggest set of new features are available for GameMode developers. GameRules now have more options to change. Waterfall and Whirlpool animations are now more cusomizable. Several new script commands were added and several old commands were given additional functionality.
You can find the full, detailed changelog here!
A decent amount of work for the big content piece of 0.60 is done, I'm not gonna jynx myself by giving even a tentative eta right now but I have some hope that when I say "soon" I don't mean "Soon™"
-Darkfire
//The Pokémon3D Team