You could download v10, install it in a separate folder and use its "Convert .TD4" function (1) to convert your database to the v8+ format. Then use the converted database (2) to see if everything is still there and works as expected.
(1) main menu: Database | Advanced | Convert .TD4
(2) main menu: Options | Preferences | Startup | Initial Database | Specific Database (with this, you can make TP10 load the converted database at startup).