how to rollback to ae cc 2019 (version 16.1.3)

hello, thanks for your time. 

I want to rollback to older version of AE. 

but my creative cloud doesn't look support 2019 version anymore. 

is there any good way to solve this problem?? 

yes, I tried link for detail down bellow of list. ( for much more older version) 

but, it says I have to enter serial number, and it keep turn back error message

any simple and good solution for this?? 

thanks again.