Beginning with myTracks 3.0 there is support for iCloud both for OS X and iOS. Once iCloud synchronization is activated all tracks and bookmarks are synchronized between all your devices. For details please read the documentation.
iCloud and the classic myTracks license
Only those Mac apps that are available on Mac App Store are allowed to use iCloud. That means that the classic version of myTracks is not able to synchronize using iCloud. Therefore I decided to provide myTracks 3.0 and any further updates exclusively on Mac App Store. Apple does not provide a solution for the migration of classic licenses into Mac App Store license. Therefore you need to buy myTracks in Mac App Store in case you still have a classic license and want to stay up-to-date. I'm sorry for that and hope that you will continue being a happy myTracks user.