Question: how to open apx file?
Answer: Ability Office by Ability Software. See the previous paragraphs to learn more about the main application. ... 
Approach (Paradox-specific Information File) by IBM. ... 
ArcPad (Ver/ 6 XML File)
C++ (Appexpert Database) by Borland Software Corporation.
TheTomb Browser (APX Webfile) by Apoltix.