The current version of Fitdigits apps can always be found on the Google Play Store.
Previous releases of Fitdigits Android Apps
iCardio * iRunner * iBiker
If you are having issues with the current version, you might try dropping down to a previous version if it worked for you. Previous versions are all iCardio, but base functionality and account information should be the same across apps.
v4.25 Jul. 31, 2018
v4.15 Nov. 14, 2017 – Last release with old home screen feed / activity results layout, and without Landscape support
v4.08 June 16, 2017 – The new user interface, material design, and much more!
v3.92 July 20, 2017
v3.78 April 7, 2017
v3.31 (pretty old…):