With version 4.5 of BlueSpice, there were two options for installation:
bluespice-deploy
container stack- Classic tarball
Based on which of those you are starting from, the update to BlueSpice version 5.1 may require different steps.
Updating from bluespice-deploy
4.5
.
├── adminPassword
├── bluespice
│ ├── _sf_archive/
│ ├── _sf_instances/
│ ├── extensions
│ │ └── BlueSpiceFoundation
│ │ └── data/
│ ├── images/
│ ├── logs/
│ ├── post-init-settings.php
│ └── pre-init-settings.php
└── simplesamlphp
├── cache/
├── certs
│ ├── saml.crt
│ └── saml.pem
├── data/
└── logs/