The flexlm (license manager) app isn't as critical as the provisioning codes, which do sometimes change a bit from version to version. But updated versions do sometimes have helpful features, especially if you are serving licenses to a large group of machines.
If you are serving a concurrent license to the desktop you are using, I would recommend updating the license manager, it's a very fast and easy install so you might as well avoid any potential issues. We usually use single-use as our ELA is pretty generous with number of licenses and it's less trouble.
Note that if you are a client to a license server, you don't need a license manager installed, you just check out your license from that server. One nice feature of that is that any license server setup and codes can serve clients from previous versions (i.e. 10.3.1 license manager can serve 9.3 desktop clients).
