The Enhanced version runs on DX12 and has a major rendering code changes update under the hood. The game has got an optimization with the features DX12 offers, including a lot of parallel rendering and computations. Given that, the new game's engine requires geometry content to be updated. This includes geometry models and texture packages.
Game's shader names are generally the same and have some internal structure changes only. This should give no impact on your models saved as .z3d files, you should be able to export them to GTAV Enhanced with no or minimum changes in ZModeler. I do not include an update of configuration script yet (the "button with gears" in materials browser), as I expect the current configurations to work fine. Yet some parameters are different and you can specify them in user-defined options. You can see the parameters list and their values upon importing vanilla game models. As before, parameter value specified in user-defined options will override the value evaluated by exporter.
The exporter requires you to specify the version explicitly. You can pick it in Export window's options area as one of drop-down selection on "Version" row: either "Legacy" or "Enhanced". Currently, ZModeler does not show any info on import whether the model you've selected a Legacy or an Enhanced one, but you can check the file version in OpenIV upon adding it into .rpf file. To the moment, OpenIV was not updated to Enhanced version and will not preview the .yft, .ydd, .ydr models from Enhanced version, so you can use this as an indication of the model version too.
I have tested only one model in game, and some game shaders are still need to be updated. If you keep getting "No shader configuration found for shader ****" on import, you can report in this topic where this error occurs - specify the missing shader name and the model file name you've got this error on.
Most of general-purpose (scenery objects) shaders and ped/player shaders were not ported yet, so to the moment you should be able to import/export vehicle models (including boats, planes etc.)
Changes to pay attention to
So far, the only difference in shaders found is an absence of some masking shaders like "vehicle_nowater" and "vehicle_nosplash". Instead, these masking options are added to any other shader. An importer will put these masking options onto material name. For example,
Legacy version: Name: "My material" Adapt: vehicle_nowater
Enhanced version: Name: "My material [NOWATER]" Adapt: vehicle_paint1
Note, the game will not render geometry (regardless of adaptation name specified) when "NOWATER" or "NOSPLASH" option name is given. This geometry will be drawn by game engine for masking-out visual effects only. Also, you can not combine these effects, you need two materials created - one for "NOWATER" masking and another for "NOSPLASH" mask.
Also, game engine supports most of modern texture formats, but ZModeler3 runs on DX11 engine. You are limited to the usage of DX11-compatible textures currently. You can use modern BC7 for transparent textures and BC5U, BC3n for normal maps.
You can use OpenRPF hook to make game load modified .rpf files from "mods" folder. This one works just fine with non-encrypted .rpf files created by current OpenIV version (use it instead of ASI Loader and OpenIV ASI plugins). Also, ScriptHook was updated recently, so ASI plugins like trainers are also available.
YTD Texture packages upgrade/conversion to/from Enhanced version
To the moment, OpenIV was not upgraded and does not handle .ytd texture packages from Enhanced version. To upgrade your textures, you can use ZModeler's exporter new option "Recreate YTD". When enabled, the texture package is create on export if any texture from this package is used in exported model's material. The texture package is composed out of all textures that are assigned to the given texture container in Textures Browser. When texture container name is among the "Preload texture packs" set (the one you can adjust on import), this texture package will not get created. For example, standard texture package like "vehshare.ytd" will not be created as long as it is listed in "Preload texture packs":
Download or update.
The update is available via automatic updates. The direct download of ZModeler3 package might include a version of filter that is not up to date.