*arr Stack + rclone Update Roundup: What to Upgrade Right Now (March 2026)
March 2026 was a busy month for the automation stack. Sonarr, Radarr, Prowlarr, and rclone all pushed releases — some routine, one with a fix that directly affects seedbox users running non-English locales. Here's a breakdown of what shipped, what matters, and the exact steps to update each component.
Quick Reference: What Dropped and When
| App | Latest Stable | Release Date | Priority |
|---|---|---|---|
| Sonarr | 4.0.17.2953 | Mar 25, 2026 | Routine |
| Radarr | 6.1.1.10360 | Mar 26, 2026 | Routine |
| Prowlarr | 2.3.5.5318 | Mar 30, 2026 | Upgrade Now |
| rclone | v1.73.3 | Mar 23, 2026 | Recommended |
Prowlarr 2.3.5.5318 — The One You Actually Need
This is the most important update in the batch. Prowlarr 2.3.5.5318 fixes a URL parsing bug that breaks on systems with non-English locales. If your seedbox is running a locale where the decimal separator is a comma (common across European VPS providers and managed seedboxes), you may have been silently getting failed searches or malformed indexer URLs without knowing it.
Key fixes in 2.3.5.5318:
Fixed: Parsing URLs on some systems due to Locale— this is the critical oneFixed: SceneTimeindexer updates (also in 2.3.4.5307 and 2.3.3.5296)- Multiple translation updates via Weblate
If you've noticed intermittent indexer failures and dismissed them as tracker downtime, this could be the actual cause. Upgrade Prowlarr first.
How to check your locale
locale | grep LC_NUMERIC
# If you see anything other than en_US.UTF-8 or C, you're potentially affected
Updating Prowlarr (Docker)
docker pull lscr.io/linuxserver/prowlarr:latest
docker stop prowlarr
docker rm prowlarr
# Re-run your original docker run command or docker-compose up -d
Updating Prowlarr (bare metal / systemd)
sudo systemctl stop prowlarr
# Prowlarr's built-in updater: Settings → General → Updates → Check for Updates
# Or manually:
cd /opt/Prowlarr
sudo -u prowlarr mono --debug Prowlarr.exe
For most seedbox users on managed platforms (Ultraseedbox, Seedhost, etc.), use the app panel's one-click update or the built-in updater at Settings → General → Show Advanced → Updates.
Sonarr 4.0.17 — Three Patch Releases in Ten Days
Sonarr pushed three releases in quick succession: 4.0.17.2950 (Mar 16), 4.0.17.2952 (Mar 19), and 4.0.17.2953 (Mar 25). The GitHub changelogs for these are sparse — the diffs show incremental fixes between minor build numbers rather than headline features.
The jump from 4.0.16.x to 4.0.17.x is the meaningful one here. If you're still on 4.0.16, update. If you're already on 4.0.17.2950 or .2952, the .2953 patch is low-urgency but worth grabbing on your next maintenance window.
Updating Sonarr (Docker)
docker pull lscr.io/linuxserver/sonarr:latest
docker compose up -d sonarr
# or if using plain docker:
docker stop sonarr && docker rm sonarr
# re-run your docker run command
Verify your running version
After updating, confirm at Activity → System → About in the Sonarr UI. You should see 4.0.17.2953.
Radarr 6.1.1.10360 — Stable Branch, Housekeeping Only
Radarr's stable release (6.1.1.10360, Mar 26) contains two commits:
- Fix for an InnoSetup download URI (Windows installer toolchain)
- SonarCloud version bump (code quality tooling)
Neither of these affects runtime behavior on Linux/Docker seedboxes. This is a safe, low-priority update. The develop branch also saw 6.1.2.10359 the same day with the same fixes.
One thing worth noting: Radarr 6.1.0.10316 (Dec 2025) added parsing support for the GiLG release group. If you're on a tracker where GiLG releases appear and Radarr was previously failing to match them, make sure you're on at least 6.1.0 before anything else.
Check your Radarr branch
Settings → General → (Show Advanced) → Updates → Branch
master= stable releases (recommended for most users)develop= pre-release, gets features faster but more risk
If you've accidentally ended up on develop and want stability, switch back to master here and let the updater pull the stable build.
rclone v1.73.3 — Patch Release Worth Taking
rclone v1.73.3 landed March 23, following v1.73.2 (Mar 6) and v1.73.1 (Feb 17). Full changelog details are at rclone.org/changelog.
For seedbox users, rclone is typically doing one of two jobs:
- Offloading completed downloads to cloud storage (Google Drive, Backblaze B2, etc.)
- Mounting remote storage for Plex/Jellyfin to stream from
Staying current on patch releases matters here because cloud provider API changes can break mounts silently. A broken mount means Plex can't see your files — and you might not notice until a user complains.
Update rclone on your seedbox
# Check current version
rclone version
# Update to latest (works on most Linux installs)
sudo rclone selfupdate
# Or re-run the install script
curl https://rclone.org/install.sh | sudo bash
If you're using rclone mount with systemd
After updating, restart the mount service:
sudo systemctl restart rclone-mount.service
# Verify it came back up
sudo systemctl status rclone-mount.service
rclone listremotes
Don't update rclone while an active mount is in use — unmount first or you risk filesystem errors.
Syncthing v2.0.15 / v2.0.16-rc — Hold on the RC
Syncthing v2.0.15 (stable) is out, and v2.0.16 release candidates are in testing. The v2.0 series introduced a significant change: the database backend migrated from LevelDB to SQLite. If you haven't upgraded from v1.x yet, be prepared for a first-launch migration that can take several minutes on larger sync setups (10,000+ files).
My recommendation: stay on v2.0.15 stable and skip the v2.0.16-rc.2 for now unless you're specifically testing. The RC adds structured logging improvements and per-package log level control — useful for debugging, not critical for production.
If you're still on Syncthing v1.x on your seedbox, the v2.0 upgrade is worth doing — SQLite is more reliable and easier to inspect if something goes wrong. Just schedule it during a low-activity window and expect the migration to run.
The 15-Minute Update Checklist
If you want to get everything current in one shot:
# 1. Update Prowlarr (highest priority)
docker pull lscr.io/linuxserver/prowlarr:latest
# 2. Update Sonarr
docker pull lscr.io/linuxserver/sonarr:latest
# 3. Update Radarr
docker pull lscr.io/linuxserver/radarr:latest
# 4. Restart all three
docker compose up -d prowlarr sonarr radarr
# 5. Update rclone
sudo rclone selfupdate
# 6. Verify versions in each app's UI
# Prowlarr: System → About → 2.3.5.5318
# Sonarr: System → About → 4.0.17.2953
# Radarr: System → About → 6.1.1.10360
Bottom Line
Prowlarr 2.3.5.5318 is the update that matters most this cycle. The locale-based URL parsing fix is exactly the kind of silent failure that's hard to diagnose — searches appear to run but return nothing, and you assume the tracker is down. If you're on a European seedbox or any system with a non-C/en_US locale, this fix is for you.
Everything else is routine maintenance. Radarr and Sonarr are stable, rclone's patch release is worth grabbing, and Syncthing users should wait for v2.0.16 to hit stable before upgrading.