what is legacy termux environment
in simple language
in termux news says the google playstore doesn't will receive Any updates.
Basically all packages are frozen with no further updates. You're on your
own if you need a later version of some software/package.
in technical term
This means typically one of these cases:
* You are running Termux on Android OS versions 5.x - 6.x.
* You have updated from Android OS 5.x - 6.x to 7.0 or higher but have not
reinstalled Termux.
Both cases result in use of legacy environment which does not receive any
updates (new packages, new app/package versions, bugfixes) and does not
receive support from devs.
Legacy environment is outdated as of 2020.01.01.