That is the latest software and it is corrupt software anyway so they stopped pushing it out. Most users have aske for rollbacks to earlier versions to solve battery drain issues. TT Sports went out of business and ceased all development almost 2 years ago so there will be no more updates.
Your account is connected to the correct server so TomTom Sports Connect should offer you the 1.7.64 build. You could enforce its installation by resetting your watch. However, since you seem to be syncing fine with Android there is no need to update.
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