Emulator Cheats

Hi... Im new to mame cheating and this site, i request help on cheat.zip editing (xml file) please forgive typo errors, english is 2nd language for me.

Basicly i know how to use the cheats , but i cant upgrade cheat.zip or edit its. xml's to get new ones.
First, i read the " xml documentation" here.. It seemed simple to update a single game xml by extracting it to cheat folder and edit it.
In my case i wanted to update my umk3.xml with various user made custom cheats found in forums. So i followed the instructions provided in xml documentation.

- extracted umk3.xml to cheat folder
- open and edit xml with new custom cheats
- save. xml

Now when i get in game.. The cheat option is no longer available in menu... After a few reset and attempts i realized my xml was faulty. So i did a step by step testing to pin-point my problem.

- deleted edited umk3.xml from cheat folder ( in game test = cheat option is back in game)

- extracted umk3.xml back from cheat.zip to cheat folder ( in game test = cheat option still there )

- open and edit umk3.xml with a single harmless typo change and saved ( in game test = no cheat option in menu)

So i assumed my saved xml wasnt working properly for i changed nothing to xml itself, aside that added a typo in a comment ( harmless change)
At this point i gave up on updating my umk3.xml... So i tryed to update the cheat.zip itself to a new version and hopefully more cheats... and i ended up with same results, still no cheat option in in-game menu, damn.

The only way cheats works properly is with its original cheat.zip file... Im confused! Why cant i update this file or properly edit .Xml

Any help would be appreciated.

EDIT : I SOLVED IT, kinda... I was using a text editor that was changing saved syntaxformat/encoding of xml. All work fine using a better text editor. So now i can upgrade my own umk3 xml.

But i still dont get why i cant update cheat.zip to latest version... I guess things changed and cheats are handeled differently in mame latest versions, then what would be latest compatible cheat.zip version?

MAME is a moving target, the cheat collection has to track the changes and that will mean that some cheats will not work in older MAME versions.

There is an archive of MAME cheat files on the cheat page, just match your MAME version and with the closest version of the cheat collection.

There may well be more cheats for any given game in the newer cheat collection, if you want to use them the best way is to update your MAME to the latest version.

Not the answer you want I know....

Well, now im kinda happy i had this issue.. For i learned how mame cheats works and how to "convert" cheats from latest mame version to the version im currently using.
Yes, i can upgrade to latest version on my pc ... But im using 0.139u1 on my android phone, thats why.

Anyways, thanks for the reply pugsy, i appreciate.

Hi. I have the same problem. I have mame 0.139u1 in android, and have the umk3.xml version than work but missing much codes and if I try edit the xml and add the missing codes the cheat option no more appear in menu options of mame in android, only appear the original umk3.xml without edit. Please someone give me a help? Thank you.