Personally, I don't see what the problem is...
Rollback of tools and add old files on next patch... that's enough to fix all problems, EXCEPT if you don't have a backup and you've screwed up your project files, but that's bad management and has nothing to do with 1.26.
On the other hand, “experimental” builds allow you to test and avoid problems once stable.

Personally?
If I had this problem I would try to do this:
1 - I'd install DayZ Tools, which have reverted to the previous version (1.25).
2 - I open my 1.25 backup of my project with TB
3 - I export the layers with the problem assets as .txt files.
4 - I edit the exported layers and add the names Geez mentioned above.
5 - I modify the .tml templates to add the legacy assets
6 - I re-import the layer exports
7 - I do a total rebuild (Terrain/Tiles)
8 - Repack with PBO Project or Addon Builder of your choice

In all honesty, it's easy to do a replace in TB, or a replace with a text editor for init.c or .DZE files. In short, nothing insurmountable, especially if you create a backup of the project before 1.26.

Hello,
One solution might be to reintroduce the asset version from v1.25 but with a different name, such as "panel_concrete_1-1.p3d", which would allow maps with exits to function by changing the name, and keep it transparent for those that haven't been impacted (which is my case).

In T184094#2688182, @DeGrinchy wrote:

+ Ok, fair enough good sir, let me ask you these questions.

Which maps are you working on?
Are these Official maps you work with editor or in game vpp admin object builder?

Are these maps your own build(s)?

And even more important, what tools are you using for packing your world? and when was your last successful pack?

there are numerous people affected by this update, trying to minimize that by focusing on one point in my post which to try and debunk the undeniable fact that this was a known and intentional issue they pushed can not be taken back not denied by anyone else my friend.

If you are going to try and tell me there was no way anyone knew this object adjustment was going to impact all maps using the object, then any conversation between yourself and I need not happen further if that is the case.

In T184094#2687606, @DeGrinchy wrote:

I am writing to address the recent DayZ update and its significant impact on community maps, particularly the changes made to commonly used game assets like "panel_concrete_1.p3d." These alterations have caused widespread disruptions, effectively rendering many community maps non-functional, as each community map has had numerous build locations completely destroyed and impassable due to now misplaced assets.... all maps of course except Namalsk -the one owned by your staff- and the three official DayZ maps. This does come across as extremely suspicious when viewed with all facts in place... however, lets move past that...

In T184094#2684962, @AGT wrote:

I tried this in order. Sadly though it did not put the panels which had been rotated back in place. Anything rotated on any axis other than the Yaw is still affected. I'll have to sort these manually because they're all rotated differently so I wouldn't be able to just alter one axis by a set amount.

Hello there,
I have experimented same issues on Experimental Build but some thinks have solved the issue :

1. Delete the directories :

Any news ?

The MessageBox appears one more time, after click on Abort, i have 2 new Error MessageBox with an MEMORY ERROR, but i have can't take it in screenshot...

The game as Crash !

Resolved on the last patch 0.58.129052 !

I have this problem on the bodies of uncouncious or dead players... i can't put on the ground any containers or weapons...