Summary of the changes in BACKCLICK 5.10.x. Newest version first. The German changelog is the reference: BACKCLICK 5 – Changelog.

Version 5.10.5 – Update of 13 November 2026 (build cfcaf546)

The version number remains 5.10.5. The update page shows the build behind it as an identifier (here cfcaf546).

• New – New interface: BACKCLICK 5 has a second, redesigned interface. It is organised by task: “Überblick” (overview), “Kampagnen” (campaigns), “Vorlagen” (templates), “Auswertungen” (reports), “Abonnenten” (subscribers), “Zielgruppen” (target groups), “Absender & Zustellung” (senders and delivery), “Benutzer & Verwaltung” (users and administration). A switch changes between the new and the classic interface at any time; the classic interface remains fully available.
• New – Campaign editor: Newsletters are built from blocks (heading, text, image, button, divider, spacing, social, product, HTML) and ready-made layouts. Test sending, link check and spam check are available directly in the editor.
• New – Reports in plain language: The result of a campaign is shown on one page: how many recipients were reached, who opened and clicked, the progression over the first 48 hours or 14 days, and the links that were clicked. Anomalies are reported as notes and compared with your own average of the last 30 days.
• New – Controlling sending: A running send can be paused, resumed and stopped; a scheduled send can be stopped. The functions are in the campaign list, in the report and in the editor. “Mail ansehen” (view mail) shows the campaign as a recipient receives it.
• New – Search: The search field in the header finds campaigns and subscribers.
• New – Name resolution: The stack includes its own DNS service, which the API, the interface and sending use for name resolution. In existing installations it starts with the second update after its introduction; until then the name resolution of the server applies.
• Improved – Performance: Reports on large campaigns and the overview are cached and recalculated only when something changes. The database memory is sized correctly even on servers with a lot of RAM.
• Improved – Deliverability: For every delivery attempt that was not delivered, the cause is recorded.
• Permissions: The menu permissions of the classic interface also apply in the new one. A user sees only the areas for which they are enabled.
• Fixed: The sending statistics showed “Fehlermails in Bearbeitung” (error mails being processed) and the block reason “Beschwerde” (complaint) as 0 from the second retrieval onwards.

Version 5.10.5

5.10.5 contains all updates that have been released since 5.10.4 under the identifiers 3c0c5a34 (5 November 2026) and d5095e23 (6 November 2026); they are listed in the two following sections. In addition:

• Security – Images in newsletters: When images are embedded, BACKCLICK no longer retrieves addresses of its own server or internal administration addresses.
• Fixed – Opens and clicks: If saving opens or clicks fails, they are written again and are no longer lost.
• Fixed – Subscription and unsubscription pages: The success page appears only if the subscription or unsubscription was actually processed.
• Security: An internal sign-in route that was no longer used has been removed.
• Quality: Two further automatic checks run before every release: no new credentials in the source code, no newly suppressed error messages.

Version 5.10.4 – Update of 6 November 2026 (build d5095e23)

The version number remains 5.10.4. The update page shows the build behind it as an identifier (here d5095e23).

• New – Optional sign-in protection: Every user can strengthen their sign-in under “Persönliche Einstellungen” (personal settings) → “Anmeldung absichern” (secure sign-in). Anyone who sets nothing up signs in as before.
• New – Second factor: After the password, a code from an authenticator app or a code by email is requested. On first setup, ten recovery codes are provided for emergencies. The QR code for the app is generated locally; setup does not need internet access.
• New – Passkeys: Sign-in without user name and password, using a PIN or biometrics on the device. The password always remains available as an alternative and then requires the second factor. Passkeys need HTTPS and a fixed domain and apply to internal accounts, not to LDAP and TAM.
• For administrators: A tenant administrator can reset a user's methods. After five failed attempts, sign-in is locked for 15 minutes. SOAP and the other machine access routes continue to require only their existing credentials.
• Fixed – Sign-in via IPv6: In older installations, signing in from an IPv6 address failed with an error message.
• Fixed – Automatic certificates: The automatic renewal of TLS certificates aborted on every run.

Version 5.10.4 – Update of 5 November 2026 (build 3c0c5a34)

The version number remains 5.10.4. The update page shows the build behind it as an identifier (here 3c0c5a34).

• New – Offline package upload: On the “Update” page, the offline package can be uploaded from your own computer directly after the package selection, with a progress bar. An interrupted transfer is resumed. The update is then started as usual; packages that are no longer needed can be removed.
• New – Offline package download: The “Update” page shows the download address and, on request, the credentials for copying. This allows the package to be downloaded on a computer with internet access.
• New – Daily backup: Optional backup service in the stack. The operator chooses the targets, including several: directory, rsync, restic or Proxmox Backup Server.
• New – Automatic certificates: The proxy can obtain and renew TLS certificates via ACME (optional, e.g. Let’s Encrypt). Existing installations keep their setting.
• New – Return to the previous version: After a successful update, update.sh --zurueck on the command line returns to the previous version. The database is kept, provided the previous version can work with it; otherwise it is restored from the backup.
• Improved – Performance: The newsletter list and statistics respond considerably faster with large data sets. The database memory is based on the available RAM and can be configured.
• Improved – Update: During an update, a notice banner appears instead of an error message, and the page reconnects by itself afterwards. After a successful update, the updater is updated automatically as well.
• Improved – Mailboxes: If a bounce or abuse mailbox requires an encrypted connection, the message now says so explicitly instead of “Invalid credentials”. After failures, the interval between attempts increases so that the mail server does not lock the access. New mailboxes start with POP3S.
• Improved – Migration of existing installations: The migration first runs in trial mode, without sending and without mailbox retrieval. Sender IPs are backed up and checked before the start; the host name is checked against the reverse DNS entry.
• Changed – Sending: The Message-ID now contains the sender domain. The obsolete DomainKey signature is generated only on explicit request; DKIM is not affected.
• Fixed: Bounce and abuse processing and other background tasks could fail to run after a container was recreated, for example after an update.
• Fixed: Addresses of up to 320 characters are stored completely in bounce and abuse processing; longer values are truncated, and the bounce mail is no longer lost.
• Fixed: The test send dialog is always within the visible area and adapts to the window size.
• Fixed: Subscriber and PDF uploads work for the system administrator even when only the file is transmitted.
• Fixed: Internal Docker addresses are no longer entered as the sender IP.
• Security: Containers run with fewer privileges; where possible, the file system is read-only.

Version 5.10.4

• New – External database: BACKCLICK 5 can use an existing MySQL 5.7 database, including a Percona cluster behind ProxySQL.
• Improved – Migration: Installations of version 5.9.74 are automatically brought to the required level 5.9.75 before the migration.
• Improved – Update page: In addition to the version number, it shows the identifier of the installed build.
• Changed: The update channel for live installations is now called “produktion”. The previous setting “aktuell” (current) remains valid and is read as “produktion”.

Version 5.10.3

• Improved: “Nach Updates suchen” (check for updates) now reports directly when the installed version is already up to date (“kein Update notwendig”, no update required); “Update starten” (start update) is then disabled.
• Fixed: Installations with a developer license show “Developer Edition” in the top right instead of “Enterprise Edition”.

Version 5.10.2

• Fixed: The version display in the top right again shows the version that is actually installed (previously it stayed at 5.9.81). It will be updated automatically with every update in future.

Version 5.10.1 – Security & new installation

• Security: Stricter access checks in the administration interface: users can only access data of their own tenant; system-wide functions are reserved for the system administrator.
• Security: Stored passwords (e.g. SMTP, mailboxes, API access) are no longer delivered to the browser. Error messages show only a reference number; details are in the server log.
• Security: Encrypted connections to LDAP and mailbox servers (LDAPS, POP3S, IMAPS) now check the certificate and the server name. User passwords are stored with a modern method (PBKDF2); existing passwords are converted automatically at startup.
• New – License key: New, digitally signed license key format. Existing license keys remain valid.
• Improved: New installations contain the standard subscriber fields; numerous individual corrections to web forms (subscription/unsubscription, profile change, forgotten password).
• Components: PDF generation on OpenPDF 3; obsolete libraries for XML and CSS processing replaced by our own maintained solutions.

Version 5.10.0 – Technical renewal

BACKCLICK 5 has been technically renewed in full. All components that are no longer maintained (end-of-life) have been replaced; functions and operation remain unchanged. Every version is automatically tested against the existing range of functions before release.

• Platform: Operation as a Docker stack on Ubuntu 26.04; Java 25 (previously Java 8), Apache Tomcat 11, Spring 7 (Jakarta EE).
• Database: MariaDB 12.3 with a current database driver; database changes are applied automatically and traceably with every update.
• New – Update at the click of a button: Updates can be searched for and installed in the administration interface under “Update” – online or as an offline package. All packages are digitally signed; if an update fails, the previous state is restored automatically.
• New – Migration of existing installations: A migration tool transfers an existing installation, including its data, to the new stack.
• Security: Central protection against cross-site request forgery (CSRF) and cross-site scripting (XSS).
• Components replaced: CORBA/JacORB by gRPC (internal communication), Apache Axis 1.4 and DWR 1.1 retired, PhantomJS/Selenium by Chrome Headless (image generation), javax.mail by Jakarta Mail; in addition, numerous libraries moved to current, security-maintained versions (including Apache POI 6, Guava 33, Log4j 2.26).
• Removed: Database connectors for Oracle, DB2 and Sybase that were no longer used.