feat: added check to let users "upgrade" from nightly to stable

feat: added check to let users "upgrade" from nightly to stable

fix: removed obsolete session id for captchas

fix: removed obsolete session id for captchas

fix: corrected typo

fix: corrected typo

chore: v4.1.0-beta release

refactor: added named arguments, fixed 404 handling

refactor: added named arguments, fixed 404 handling

feat(editor): added delete button, closes thorsten#3765