Yeah, the thing is if you have an otserv with the tibia version lower than 9.0, you can download OTItem Editor, which will change the item.otb, in data/itens.
after done that you have to open the program and load your .otb file, like this:
View attachment 9863
when done, go in "others", select id 7368, and uncheck stackable, like this:
View attachment 9864
When done that save it.
the thing is will need the .dat and .spr from the tibia version you want to use, so copy it and put in the otitemeditor / data folder, change the spr and dat to like tibia910.spr and tibia910.dat, for the version 9.1 i didn't find a item editor yet but i'm sure will be one soon, the last version i found is
Download.
if i helped you please rep++
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sorry for the low quality pictures