Post-it® Digital Notes 5.3

Just upgraded (should say downgraded) to V. 5.3.0.0070. Update deleted ALL of my notes and ALL of my memoboards. The Data file - PDNDB according to the "Help" screens - was in such an obscure place. And now the new version does not even create that particular data file. Am able to save the one memo board and the test note I placed on it, but notes on the desktop disappear into a cyberspace black hole of some sort.