I just submitted the new strings for Moodle Mobile 3.1.3.
You can find the strings to be translated in the component: local_moodlemobileapp version 2.6 (you only need to translate the strings for that version, no need to copy the strings in following ones).
Moodle Mobile 3.1.3 will be released the next week (Wednesday or Thursday).
This new version comes with offline support improvements.
Thanks for your contributions! Juan