Lightroom 5.7 desktop but want to upgrade to iOS 64 bit

If you purchase (subscribe) to Lightroom Classic, everything works on Catalina and you won't lose information. I don't think the order matters (although you may not be able to install Lightroom Classic if your operating system is too old)

Hi there,

Lightroom 5 is not compatible with Mac OS Catalina and we do not recommend that you upgrade your OS. 

See this tech note for more details: https://helpx.adobe.com/in/lightroom-classic/kb/macos-catalina-compatibility.html

We'd recommend that you upgrade to Lightroom Classic as the transition from Lightroom 5 to Lightroom Classic and Lightroom desktop is quite easy and smooth.

First, you need to install the new Lightroom version and then open your existing catalog in the new version. Lightroom will then automatically prompt you to upgrade the catalog, checkout this article for details: https://helpx.adobe.com/in/lightroom-classic/help/create-catalogs.html#upgrade_a_catalog 

If you have any other questions, don't hesitate to let us know. 

Thanks,

Akash