How to update snap from stable version to last version

Sorry for the stupid question, but I can’t find in the internet how to upgrade the version of the snap from stable to the latter. Now it’s kind of like 2.26.14

I do it because of interfaces.

snap info core <-- will tell you what versions are in which channels

snap refresh core --beta <-- to switch to another channel
(or --candidate or --edge if you want one of the other channels)

you can switch back the same way via “snap refresh core --stable” if you are done with testing and/or the interface change landed in stable …

Note that “last version” is somewhat ambiguous. Every snap may define multiple channels, and each channel will offer you a line of revisions. You can find what the last revision on each available channel is by running snap info <snap name>.