Some releases are safe to upgrade to, needing no changes. A few need a small hotfix patch. All upgrades will break apps, even if your jailbreak survives - but

Some releases are safe to upgrade to, needing no changes. A few need a small hotfix patch. All upgrades will break apps, even if your jailbreak survives - but re-installing apps is a breeze. And finally, a few releases might brick your jailbreak badly. The guidance usually is to “Avoid upgrades, and check the forum thread when a new release is available to see the safe way to upgrade”.