An software update is necessary at different intervals. Optimizations are often carried out or security gaps are closed. In case you need to update your masternode because of a maintenance release and your setup is done manually you have to take a few steps.
If you use the Poseidon One-Click Setup you normally don´t have to take any actions for updates because Poseidon takes care of it.
A masternode consists of two processes which are running on your Linux system. A process is basically a file in your file system which is loaded into your memory for doing operations. It is good practice to keep these booth files at the following location:
/usr/bin/pirl # pirl node
/usr/bin/marlin # pirl ipfs
For a manual update we stop these booth services, replace the files in the file system and start the services again. Depending on your masternode type please follow the appropriate link.