For the time being the SolarWinds agent on Linux is only compatible with Python 2.x
Python is already available in version 3.7.x. and version 2.x will be end of life by the end of the year. Update Python 2.7 EOL date by hugovk · Pull Request #344 · python/devguide · GitHub
A funny site to follow Python 2.7 Countdown to know when Python 2 will be end of life
Cheers