On behalf of Adobe …
The first 64-bit version of Acrobat for MacOS was Acrobat Pro DC / Acrobat Pro 2015. Earlier versions of Acrobat are no longer supported or updated. Acrobat 10 was the “current” version of Acrobat between November 2010 and October 2012.
If you update your MacOS to 10.15 which will require all programs to be 64-bit, you will also need to license Acrobat Pro 2017 or subscribe to Acrobat Pro DC. If you don't want to upgrade your applications, simply stay with MacOS 10.14 – That is your choice. FWIW, Adobe doesn't control or can even influence Apple's propensity to have OS releases that do not maintain the ability to run existing application software versions.
- Dov