@mineo
there are always difference between two BuddyPress version…. If you use a custom translation, you must update your version at each BP update. This is how translating a plugin or a theme works and has nothing to do with php files or studying the support.
Version 2.0
Version 2.0.1
Version 2.0.3
Version 2.1
and so on…
For example, the difference between 2.0.1 and 2.1 is not the translation itself, but the translation comments who where added for better disambiguation.
So for example the word “activity’ in bp 2.01 is written in the po file like this:
#: bp-activity/bp-activity-loader.php:165
#: bp-activity/bp-activity-loader.php:276
msgid "Personal"
msgstr ""
and in BP 2.1, you see this:
#: bp-activity/bp-activity-loader.php:277
msgctxt "My Account Activity sub nav"
msgid "Personal"
msgstr ""
A comment was added who look like this: msgctxt "My Account Activity sub nav"
Because of this comment, even if the phrase is already translated, poEdit consider that there is a modification and mark this phrase as fuzzy. And because it is fuzzy, gettext doesn’t use it and the word stays in english.
In 2.1 “activity” remains 9 times alone, with 9 different disambiguation context, in difference to older versions where “activity” was used indifferently for any context.
So if you didn’t take care of such difference, you can think your word is translated. It is, but outside of the context.
msgctxt "Page title for the Activity directory."
msgid "Activity"
msgctxt "Activity items per page (screen options)"
msgid "Activity"
msgctxt "Admin Dashbord SWA page title"
msgid "Activity"
msgctxt "Admin Dashbord SWA menu"
msgid "Activity"
etc
This means of course that you have to translate “activity” 9 times, instead one time, but the avantage to write it differently, depending your language and the context where the word is used.
And again, modifying a po file with a text editor without compiling it into mo format is unuseable. You must use a compiler like poEdit, as gettext use .mo file to translate.
Po/pot files are only working files, not system files like mo is.