V1.5.1 is a maintenance update.
- Expanding the calc, via tap on ND1 when ND1 is already selected, now works on iOS 7 too.
- There's a new preference in the Settings app under ND1 for hiding the status bar.
In addition, V1.5 had three bad regressions, which have been fixed:
- on iOS 6, double-tapping is no longer finicky
- in alg mode, the Ans key now works as expected
- entering RPL programs works without error msg (these would occur in 1.5 when there was whitespace past any RPL end marker)
Also, check your downloadables for updates. Several folders have been updated.
There're no key/function changes with 1.5.1, so no need to restore the calculator. (Provided you restored with v1.5. Your function count on the Definition page should be 500.)