chore: Add blog post for Themerr release v2026.1008.3030

[LizardByte-bot]

‼️ Attention: Themerr now supports Plex and Jellyfin!

Themerr-plex has been renamed to Themerr! Manage Plex and Jellyfin servers from the same standalone application, with shared library browsing, theme playback, and processing history. This release also provides a migration path from the older Themerr-jellyfin plugin. (#600)

⚠️ Breaking changes and migration notes

• Update launchers and Docker references. Release archives now use the Themerr name. Launch themerr, or themerr.app on macOS, and update Docker deployments to lizardbyte/themerr. Preserve your existing configuration directory or /config volume to retain saved settings, server connections, and history.
• Keep your existing credential encryption key. Docker and headless installations use THEMERR_TOKEN_KEY_FILE. The previous THEMERR_PLEX_TOKEN_KEY_FILE name remains supported; use the same key file when changing the variable name. This key also protects saved YouTube cookies.
• Review Jellyfin migration settings before connecting. Connect through Servers > Jellyfin using a Jellyfin API key. By default, Themerr recognizes unchanged themes from the older Themerr-jellyfin plugin and removes that plugin and its repository after connecting. These preferences are available under Settings > Jellyfin.
• Make Themerr reachable from Jellyfin. Save a Themerr address on the connected server card so Jellyfin can install its connector. With Themerr's default self-signed certificate, use the connector repository on HTTP port 9495 and publish that port in Docker. Use an address reachable from the Jellyfin server; localhost inside another container refers to that container.
• Older Plex plugin installations still require migration. If upgrading from v2024.813.13709 or earlier, follow the standalone application migration notes before starting this release.

✨ Highlights

• Jellyfin integration. Add themes to movies, series, and collections on Jellyfin 10.11.x and stable Jellyfin 12.x starting at 12.1, including 12.2. Existing user themes are protected by default, with optional replacement and backups. (#600, #613)
• Automatic Jellyfin connector management. Themerr installs and updates the matching connector, waits for playback to finish before automatic restarts, and fixes connector replacement restart loops. (#600, #606)
• Remote Plex cleanup over SSH. Remove older uploaded themes, posters, and artwork through SFTP when Plex runs on another machine. Configure password or private-key authentication with server fingerprint verification directly from the updated server cards. (#619)
• Safer YouTube cookie storage. Saved cookies are encrypted and masked in Settings, with explicit controls to reveal, replace, or clear them. Existing saved cookies are encrypted automatically when upgrading. (#612)
• Accurate ThemerrDB deployment status. The deployment indicator now reads the timestamp from ThemerrDB's published metadata. (#615)
• Updated Docker packaging. Docker images now use an Alpine runtime with the packaged Themerr application and bundled Jellyfin connectors. (#625)

For a comprehensive list of changes, see below.

What's Changed

• feat: support Jellyfin and rename repo to Themerr by @ReenigneArcher in #600
• chore(deps): lock file maintenance by @renovate[bot] in #601
• chore(deps): update dependency lucide to v1.52.0 by @renovate[bot] in #603
• chore(l10n): update translations by @ReenigneArcher in #604
• chore: add sonar property files by @ReenigneArcher in #605
• fix(jellyfin): prevent connector replacement restart loops by @ReenigneArcher in #606
• ci: reuse preinstalled OpenSSL on Windows ARM64 by @ReenigneArcher in #610
• fix: securely store YouTube cookies by @ReenigneArcher in #612
• feat(jellyfin): support compatibility series and runtime validation by @ReenigneArcher in #613
• chore(l10n): new babel updates by @LizardByte-bot in #614
• fix: read ThemerrDB deployment timestamp from published metadata by @ReenigneArcher in #615
• fix(l10n): keep JavaScript extraction consistent across platforms by @ReenigneArcher in #617
• feat: add secure Plex SSH cleanup and refine server cards by @ReenigneArcher in #619
• chore(deps): update mcr.microsoft.com/dotnet/sdk docker tag to v11 by @renovate[bot] in #618
• chore(l10n): update translations by @ReenigneArcher in #607
• chore(deps): update official github actions by @renovate[bot] in #620
• chore(deps): update dependency sqlalchemy to v2.1.4 by @renovate[bot] in #623
• chore(deps): update dependency fastapi to v0.142.4 by @renovate[bot] in #624
• build(docker): package Themerr in an Alpine runtime image by @ReenigneArcher in #625
• chore(deps): lock file maintenance by @renovate[bot] in #622

Full Changelog: LizardByte/Themerr@v2026.1004.152244...v2026.1008.3030

---

Contributors

---

📦 Assets:

⬇️ Download	#️⃣ Download Count	🛡️ VirusTotal
Themerr_Linux_aarch64.zip
Themerr_Linux_x86_64.zip
Themerr_Windows_AMD64.zip
Themerr_Windows_ARM64.zip
Themerr_macOS_arm64.zip
Themerr_macOS_x86_64.zip

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (0deb3ac) to head (50a0f9d).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff            @@
##            master      #487   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           10        10           
  Lines         1000      1000           
  Branches       132       132           
=========================================
  Hits          1000      1000           

---

Continue to review full report in Codecov by Harness.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 0deb3ac...50a0f9d. Read the comment docs.

🚀 New features to boost your workflow:

• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.