Can I upgrade to 7.3 w/o overwriting language keys

I've noticed that the upgrade to v7.3 includes langs > en.php files for each module.

I have customized a number of language keys for each of my sites' niches.

Can I upgrade & recompile without overwriting existing language keys, while allowing new keys to still be added?

If so, how?

Thanks!

Upgrading will not affect language keys that you have added.  Of course you should back up your database and site files; all of them, before performing any upgrades.

What about the language keys that I didn't add, but changed?

For instance: in the sites modules...

'_bx_sites_bcaption_description' => 'Description',

I changed to (several versions ago)

'_bx_sites_bcaption_description' => 'A Brief Overview',

Will upgrading to 7.3 overwrite my previous change & revert it back to 'Description'?

Upgrade will change only keys which was changed/deleted during the upgrade it doesn't affect other language keys.

The action which resets modules languages is "Recompile Language(s)" in Admin Panel > Modules > Add & Manage - don't do it.

Anyway it's better to backup everything before making upgrade.