# StartOS v0.4.0

## Warning

Previous backups are incompatible with v0.4.0. It is strongly recommended that you (1) immediately update all services, then (2) create a fresh backup. See the [backups](#improved-backups) section below for more details.

## Summary

A server is not a toy. It is a critical component of the computing paradigm, and its failure can be catastrophic, resulting in downtime or loss of data. From the beginning, Start9 has taken a "security and reliability first" approach to the development of StartOS, favoring soundness over speed, and prioritizing essential features such as encrypted network connections, simple backups, and a reliable container runtime over nice-to-haves like custom theming and more services.

Start9 is paving new ground with StartOS, trying to create what most developers and IT professionals thought impossible: an OS and user experience that affords a normal person the same independent control over their data and communications as an experienced Linux sysadmin.

The difficulty of our endeavor requires making mistakes, and our integrity and dedication to excellence require that we correct them. This means a willingness to discard bad ideas and broken parts, and if absolutely necessary, to tear it all down and start over. That is exactly what we did with StartOS v0.2.0 in 2020. It is what we did with StartOS v0.3.0 in 2022. And we are doing it now with StartOS v0.4.0 in 2026.

v0.4.0 is a complete rewrite of StartOS — almost nothing survived. After nearly six years of building StartOS, we believe we have finally arrived at the correct architecture and foundation to deliver on the promise of sovereign computing.

## Changelog

### User Experience

#### New User Interface

The StartOS UI has been rewritten to be more performant, more intuitive, and better looking on both mobile and desktop.

#### Internationalization

StartOS v0.4.0 and available services now support multiple languages and keyboard layouts.

#### Improved Actions

Actions accept arbitrary form input and return arbitrary responses, replacing the old "Config" and "Properties" concepts, which have been removed. The new Actions API gives package developers the ability to break configuration and properties into smaller, more specific forms — or to exclude them entirely without polluting the UI. Improved form design and new input types round out the experience.

#### Progress Reporting

A new progress reporting API enables package developers to define custom phases and provide real-time progress updates for operations such as installing, updating, or backing up a service.

#### Email Notifications via SMTP

You can now add your Gmail, SES, or other SMTP credentials to StartOS to deliver email notifications from StartOS and from installed services that support SMTP.

### Networking & Connectivity

#### LAN Port Forwarding

Perhaps the biggest complaint with prior versions of StartOS was the use of unique `.local` URLs for service interfaces. This has been corrected. Service interfaces are now available on unique ports, supporting non-HTTP traffic on the LAN as well as remote access via VPN.

#### Gateways

Gateways connect your server to the Internet, facilitating inbound and outbound traffic. It is now possible to add Wireguard VPN gateways to your server to control how devices outside the LAN connect to your server and how your server connects out to the Internet. Outbound traffic can also be overridden on a per-service basis.

#### Private Domains

A private domain is like your server's `.local` address, except it also works over VPN, and it can be _anything_ — a real domain you control, a made-up domain, or even a domain controlled by someone else.

Like your local domain, private domains can only be accessed when connected to the same LAN as your server, either physically or via VPN, and they require trusting your server's Root CA.

#### Public Domains (Clearnet)

It is now easy to expose service interfaces to the public Internet on a domain you control. There are two options:

1. **Open ports on your router.** This option is free and supported by all routers. The drawback is that your home IP address is revealed to anyone accessing an exposed interface.

2. **Use a Wireguard reverse tunnel**, such as [StartTunnel](#start-tunnel), to proxy web traffic. This option requires renting a $5–$10/month VPS and installing StartTunnel (or similar). The result is a virtual router in the cloud that you can use to expose service interfaces instead of your real router, hiding your IP address from visitors.

#### Let's Encrypt

StartOS now supports Let's Encrypt to automatically obtain SSL/TLS certificates for public domains. Visitors to your public websites and APIs will no longer need to download and trust your server's Root CA.

#### Internal DNS Server

StartOS runs its own DNS server and automatically adds records for your private domains. You can configure your router or other gateway to use the StartOS DNS server to resolve these domains locally.

#### Static DNS Servers

By default, StartOS uses the DNS servers it receives via DHCP from its gateway(s). It is now possible to override these with custom, static DNS servers.

#### Tor as a Plugin

With the expanded networking capabilities of StartOS v0.4.0, Tor is now an optional plugin that can be installed from the Marketplace. Users can run their own Tor relay, route outbound connections through Tor, and generate hidden service URLs for any service interface, including vanity addresses.

#### Tor Address Management

StartOS v0.4.0 supports adding and removing Tor addresses for both StartOS itself and all service interfaces. You can even provide your own private key instead of using one auto-generated by StartOS, enabling vanity addresses.

### System & Infrastructure

#### LXC Container Runtime

Neither Docker nor Podman offer the reliability and flexibility needed for StartOS. Instead, v0.4.0 uses a nested container paradigm based on LXC for the outer container and Linux namespaces for sub-containers. This architecture naturally supports multi-container setups.

#### Hardware Acceleration

Services can take advantage of — and require — the presence of certain hardware modules, such as Nvidia GPUs, for transcoding or inference. For example, StartOS and Ollama can run natively on the Nvidia DGX Spark and take full advantage of its hardware and firmware stack to perform local inference against open source models.

#### Squashfs Images for OS Updates

StartOS now uses squashfs images instead of rsync for OS updates, enabling better update verification and improved reliability.

#### Replaced PostgreSQL with PatchDB

StartOS itself has minimal data persistence needs. PostgreSQL was overkill and has been replaced with the lightweight PatchDB.

#### Improved Backups

The new `start-fs` FUSE module unifies filesystem expectations across platforms, enabling more reliable backups. The system now defaults to rsync differential backups instead of incremental backups, which is both faster and more space-efficient — files deleted from the server are also deleted from the backup.

#### SSH Password Authentication

You can now SSH into your server using your master password. SSH public key authentication is still supported as well.

### Developer Experience

#### New S9PK Archive Format

The S9PK archive format has been overhauled to support signature verification of partial downloads and direct mounting of container images without unpacking the archive.

#### TypeScript Package API and SDK

Package developers can now interact with StartOS APIs using the new `start-sdk`, available in TypeScript. A barebones StartOS package (S9PK) can be produced in minutes with minimal knowledge or skill. More advanced developers can use the SDK to create highly customized user experiences for their services.

#### Registry Protocol

The new registry protocol separates package indexing (listing and validation) from package hosting (downloading). Registries are now simple indexes that reference binaries hosted in arbitrary locations, locally or externally. For example, when someone visits the Start9 Registry, the curated list of packages comes from Start9, but when they install a service, the binary is downloaded from GitHub. The registry also validates the binary. This makes it much easier to host a custom registry, since it is just a curated list of services that reference package binaries hosted on GitHub or elsewhere.

#### Exver and Service Flavors

StartOS now uses Extended Versioning (Exver), which consists of three parts: (1) a semver-compliant upstream version, (2) a semver-compliant wrapper version, and (3) an optional "flavor" prefix. Flavors are alternative implementations of a service where a user would typically want only one installed, and data can be migrated between them. Flavors commonly satisfy the same dependency API for downstream packages, though this is not strictly required. A valid Exver looks like: `#knots:29.0:1.0-beta.1` — the first beta release of StartOS wrapper version 1.0 of Bitcoin Knots version 29.0.
