These builds are triggered automatically by commits to the master branch. They are experimental and intended for testing. Use at your own risk. That said, if the latest version has been there a while (perhaps a week or so) its likely been tested in that time and probably ok for general use. See the project on GitHub for more details.
More stable builds are experimentally available via this F-Droid repository: onosendai.herokuapp.com/repo
onosendai_483_2018-06-23_17-04-08.apk
onosendai_482_2018-06-23_11-04-06.apk
onosendai_481_2018-01-06_20-04-06.apk
onosendai_480_2018-01-06_19-04-06.apk
onosendai_479_2017-10-28_19-04-06.apk
onosendai_478_2017-10-21_17-04-08.apk
onosendai_477_2017-10-21_16-04-08.apk
onosendai_476_2017-10-21_15-04-07.apk
onosendai_475_2017-10-21_13-04-07.apk
onosendai_474_2017-10-10_21-04-06.apk
onosendai_473_2017-10-07_11-04-10.apk
onosendai_472_2017-10-06_23-04-08.apk
onosendai_471_2017-10-05_08-04-10.apk
onosendai_470_2017-10-04_22-13-32.apk
onosendai_469_2017-10-04_21-04-08.apk
onosendai_468_2017-10-03_23-04-08.apk
onosendai_467_2017-09-18_22-49-16.apk
onosendai_466_2017-09-06_19-09-07.apk
onosendai_465_2017-06-13_20-45-32.apk
onosendai_464_2017-06-12_23-09-06.apk