Upgrading to the latest release from 7.1 is not supported. You would require to go first to 12.6.
This is documented on the TechDocs, documentation. You can find the upgrade path there:
r7.1 upgrade to V13.0.3 64-bit Non-Windows server:
To upgrade from r7.1 to V13.0.3, you must upgrade the r7.1 server to r12.6 32-bit server and then, proceed to upgrade to V14 64-bit server.
Example: r7.1 Linux 32 bit Server ---> r12.6 Linux 32bit Server ---> V14.0 Linux 64-bit Server
As there is no 64-bit support for 7.1 installation, during upgrade process you must upgrade to 32-bit installation of r12.5 and then upgrade to the 64 bit installation of V14.0
You can find on the doc as well the supportability matrix to see what are the requirements you need to meet in terms of OS/DB (as you will most probably need to upgrade them too):