Written by Adam Wien – Product Manager

Comet 26.4.0 Phoebe

Comet 26.4.0 Phoebe, our latest Quarterly release, brings new features that expand how you can access and manage Comet Backup. Highlights include a native cPanel plugin for seamless hosting-panel integration, Proxmox guest quotas for better resource control, and Storage Template replication across management consoles for simplified multi-server environments. This release also adds Czech language support, updates to our Ukrainian translation, and an important fix for a Microsoft 365 Graph API issue that affected backup providers industry-wide.

The full set of changes can be found in the release notes.

Why Phoebe?

This Quarterly release is named after Saturn’s moon Phoebe.

Fun fact: Phoebe is one of Saturn’s most unusual moons. It orbits in the opposite direction (retrograde) to nearly all of Saturn’s other moons, which strongly suggests it was captured from the Kuiper Belt rather than forming alongside Saturn. Its surface is exceptionally dark, reflecting only about 6% of the sunlight that hits it, making it one of the darkest objects in the Solar System. NASA’s Cassini spacecraft flew by Phoebe in 2004, revealing a heavily cratered, ancient world rich in ice and carbon, a relic from the earliest days of our solar system.

Webinar Announcement

Join us for our Quarterly webinar on Tuesday, May 13th, 2026 (4pm ET / 1pm PT). Comet Backup’s Product Manager, Adam Wien, and Engineering Manager, Callum Sinclair, will cover all the latest product updates, with a live question-and-answer session at the end.

Register for the webinar here.

New Feature: cPanel Plugin

Comet Backup is now available as a native cPanel plugin, bringing enterprise-grade backup directly into the world’s most popular hosting control panel.

For WHM administrators, this means you can set up, schedule, and manage per-account backups entirely within WHM — no external tools or separate management consoles required. The plugin handles everything from activation and storage provisioning to backup scheduling and per-account restores, all from the interface you already use every day.

Key benefits:

• Fully integrated in WHM — Create and manage backup jobs, configure schedules, and restore accounts directly from the WHM Plugins section, with no external software or dashboards to manage

• Per-account backups and restores — Back up and restore individual cPanel accounts including files, databases, email, and account settings, designed for multi-tenant hosting environments

• Incremental and deduplicated — Backups are incremental with server-wide deduplication, minimizing storage usage and keeping backup windows short

• Flexible scheduling and retention — Configure backup schedules and retention policies that fit your hosting business, from daily account backups to on-demand runs

Whether you’re a shared hosting provider looking to offer reliable backup protection or a server administrator who needs real disaster-recovery capability for cPanel accounts, the Comet Backup cPanel plugin delivers a complete, integrated solution. If you’re already a cPanel partner, reach out to your account manager to get started.

New Feature: Proxmox Guest Quotas

Comet 26.4.0 Phoebe introduces guest quotas for Proxmox environments, giving partners fine-grained control over the number of virtual machines and containers that can be backed up per user.

This feature is especially valuable for Managed Service Providers (MSPs) who need to manage backup costs and set clear boundaries for their customers’ Proxmox environments.

How it works:

• Set a maximum number of Proxmox guests (VMs and containers) that a user is allowed to back up
• The quota is configured per user in the Comet Management Console
• If a user attempts to back up more guests than their quota allows, the backup job will return a clear error message, preventing unexpected usage growth

Why it matters:

• Cost control for MSPs — Align backup capacity with your service tiers and pricing plans
• Predictable resource usage — Prevent any single customer from consuming more Proxmox backup capacity than allocated
• Clear customer communication — Transparent quota limits that customers can see and understand

New Feature: Storage Template Replication

Storage Templates can now be replicated as part of the Management Console replication feature. For organizations running multiple Comet management consoles, whether for redundancy, geographic distribution, or organizational separation, this means your storage configurations stay consistent across all consoles automatically.

Previously, storage templates had to be configured independently on each management console. With 26.4.0 Phoebe, when you configure replication between management consoles, your storage templates are included automatically. Any changes made to storage templates on one console will be replicated to the others.

Benefits:

• Reduced configuration overhead — Set up storage templates once and have them automatically available across all your management consoles
• Consistency — Ensure all your consoles offer the same storage options to users, eliminating configuration drift
• Simplified disaster recovery — If a management console needs to be rebuilt, storage templates are restored automatically as part of the replication

New Language Support

Czech Language Translation

Comet Backup now features a Czech (Čeština) language translation, contributed by the community through our open-source translations repository on GitHub. This brings Comet’s total to 17 supported languages, making it easier for Czech-speaking partners and end users to manage their backups in their native language.

Updated Ukrainian Translation

We’ve also updated our Ukrainian (Українська мова) translation with improved accuracy and coverage, which was initially introduced in Comet 26.1.0 Iapetus.

We welcome contributions from the community to help bring Comet Backup to more languages. Visit our translations repository on GitHub to contribute.

Enhancements

Comet 26.4.0 Phoebe includes numerous enhancements across the platform. These improvements increase reliability, streamline daily operations, and address community feedback. A full list of enhancements and bug fixes can be found in our release notes.

Management Console:

• Automatic redirect to new job’s report page when triggered through the web UI
• Allow easily selecting groups of snapshots to search for restore or to delete
• Added a lock/unlock button to password and bucket ID fields to prevent password manager autofill
• Added custom general-purpose metadata fields to the User Profile for use via the API

Proxmox:

• Detect user inadvertently entering the Proxmox Web UI port number (8006) for the SSH port
• Fixed issues with Proxmox restore to Ceph/RBD storage
• Fixed issues with Proxmox storage names containing upper-case letters

Security & Reliability:

• Added warning message if configuring a webhook integration over insecure HTTP
• Added internal mongodump functionality, removing dependency on external executables
• Fixed an issue where Comet Core would fail to start if the Storage Gateway failed to validate storage buckets
• Improved handling of symlinks during restore on Linux

Backup Agent:

• Improved MySQL backup performance with optimized dump flags
• Fixed login dialog refresh issues in the Comet Backup desktop app
• Improved Linux Recovery Media with automatic internet time sync
• Fixed Recovery Media generation from Podman Desktop-based Docker environments

Addressing the Microsoft 365 Graph API Issue

Earlier this month, an upstream bug in Microsoft’s Graph API caused Calendar Events delta queries to enter an infinite loop, returning unbounded data to any application requesting calendar sync updates. This was an industry-wide issue that affected backup providers across the board — not specific to Comet.

The impact for Comet customers was that some Microsoft 365 backup jobs became stuck or failed due to excessive memory consumption as the backup agent tried to process the never-ending API response.

Our engineering team identified the root cause, traced it back to Microsoft’s API behavior, and built a fix into Comet 26.4.0 Phoebe. The fix introduces safeguards that detect when a Graph API delta query returns an abnormally large or unbounded dataset. Rather than consuming memory indefinitely, Comet now identifies this condition, terminates the runaway request, and falls back to a safe recovery path — allowing backup jobs to complete successfully without manual intervention.

We also proactively communicated with all affected MS365 customers as soon as the issue was understood, so partners could set expectations with their own clients.

Even though this was a Microsoft-side bug, we believe Comet should be resilient to unexpected behavior from third-party APIs. This fix makes Comet more robust against similar upstream issues in the future, and we’ll continue to invest in defensive engineering to protect your backups. If you have any questions, please reach out to us at [email protected].