Also after a click on Help - Update application BL Banking reports that no update is available.
Possibly the program was installed into a write protected directory. This is described in chapter General - Installation - Installation scenarios - Separate data storage. In this case BL Banking must be started by an operating system user with administrator rights. See also FAQ 34.
Furthermore, it could be that the function Automatic updates in the preferences is disabled.
Another possibility is that your Internet Explorer probably still has an outdated update page in its cache. BL Banking loads this page to check for available updates. To update this page immediately, load the page https://www.blbanking.de/site.xml and click Update in the Internet Explorer. This page should then indicate the respective latest version number. BL Banking then also recognizes that its own version number is no longer up to date.