Actually, 2.5.1 will say 2.5.0 on the dashboard because they did not ( ans likely will not) update openhab-core. 2.5.1 is designed so addons updates dab be released separately from the rest of openHAB.
I am away from home for the week so I cannot test to verify.
Please also be aware that the footer of the dashboard will still say “openHAB 2.5.0 Release Build” - this is because the version of the core runtime is show, which has not been touched at all. To see the detailed version information, please have a look at userdata/etc/version.properties , which should look like:
openHAB Distribution Version Information
----------------------------------------
build-no : Release Build
online-repo : https://openhab.jfrog.io/openhab/libs-release
Repository Version
----------------------------------------
openhab-distro : 2.5.1
openhab-core : 2.5.0
openhab1-addons : 1.14.0
openhab2-addons : 2.5.1
karaf : 4.2.7