Unfortunately the last iOS based VitaDock+ app update caused a small bug which prevented all our iOS users to proceed over 8% with their sync process if they were born before year 1975.
Because of that we have set the birth year for all our iOS users who are born before 1975 to 1980 by default to avoid this error until the next app update is released.
After the release the possibility to set one's own birth year freely will be allowed again to this concerned group of iOS users. Forcing a change of the set birth year is not recommended, as it will be changed to 1980 with the next sync process anyway.
Please excuse eventual inconvieniences in this matter.