Gdal version error in Centos7 running script


I use Centos7 and Chrome. I successfully processed the sample images using WebODM in Docker a few weeks ago but later the application didn’t start, saying it needs python3 and gdal 2.1. I got around the python issue but cannot find a way to install/set the gdal 2.1 environment variable.
Could somebody please send me in the right direction? Much appreciated. Here is what the error in the file says:
You’re almost there!

Your system is currently using a version of GDAL that is too old, or GDAL is not installed. You need to install or configure your system to use GDAL 2.1 or higher. If you have installed multiple versions of GDAL, make sure the newer one takes priority in your PATH environment variable.