Modding "main unit" entries, possible consequences when patched?

[Gauloisier de la Gauloiserie]

Hi there
A question to all veteran modders out here: if a mod (mine for instance hehe) modifies the main unit file/entry in db, how possible is it that I'll have to redo my mod if CA releases a patch or DLC?
In previous TW games, when they released patches or DLC, there were new files in /data, usually called patch1.pack, patch2.pack and so on. I can be mistaken but I think that they never touched or altered the original pack containing "main entry", which means that technically you were pretty safe with the mod and it continued to work even after patches.
But so far in R2TW they have directly modified the main pack file.
How probable is it that our modded main unit (or other modified pcak entries) will work with future patches?
I bet that new added entries, like new units are pretty safe anyway, as they are "added" lines to the files, and not modified ones?
Thanks for help

[daniu]

If you're modding the main_units in data_rome2.pack directly, it will certainly be overwritten each patch which is exactly why you shouldn't do that.
If you have kept it in your own pack file like you should, it will work if the structure of main_units didn't change.
If it did, it may still work, but PFM also has an automatic upgrade feature.

[Gauloisier de la Gauloiserie]

Thanks for your reply!
I'm using my own pack file dont worry.
When you say "if the structure of main_units didn't change", you mean the amount of vertical rows (parameters)?
Does it happen often?
I thought that patches only modify the cells content or add additional horizontal rows for new units

[Aodh Mor]

and it makes it easier if you keep 2 version of the mod, 1 for working on, and one for playing with the DB's minimised using the PFM to only what you're changing, and then just add a prefix to all the tables, I'm using RRR_ for RRR, just make sure it something ppl probably wont use for their own mods