# Stalwart 1.0 stabilises self-hosted mail storage — but existing servers need a one-time migration The Rust mail and collaboration server's first stable release commits to a durable database format, rewrites search and parsing, and publishes extensive vendor-run comparisons with Postfix/Dovecot. Operators must migrate older stores; clusters now require Redis. Stalwart 1.0 ships stable mail storage, new search and performance improvements; existing v0.16 installations need a migration tool, and clustered setups need Redis. - Status: Active - Published: 2026-10-27T16:24:38+13:00 - Updated: 2026-10-27T16:24:38+13:00 - Categories: SaaS, Cloud & Infrastructure, Marketing & Distribution, Hosting, Email & Lifecycle, SaaS Operations - Tags: IMAP, JMAP, mail servers, migration, open source, self-hosted email, SMTP, Stalwart - Canonical HTML: https://beyondthe.news/dossiers/stalwart-1-0-mail-server-stable-schema-migration-postfix-dovecot-benchmarks ## What changed Stalwart released v1.0 on October 26, 2026, its first stable mail/collaboration server release after five years. The Rust-based server supports SMTP, IMAP, POP3, JMAP, CalDAV, CardDAV and WebDAV. Version 1.0 finalises the on-disk database layout, substantially rewrites MIME parsing and storage/search paths, adds full-text search inside document attachments and expands authentication controls. Its maintainers publish benchmark scripts and report winning 35 of 38 comparisons against a configured Postfix 3.11 and Dovecot 2.4 stack, but those results remain vendor-run. Crucially, v1.0 cannot directly open pre-1.0 data stores: v0.16 operators must first reach 0.16.27 and run stalwart-migrate; older versions can use a migration proxy and Vandelay. Clusters now require Redis coordination. ## Why it matters For a small team operating its own mail, the difference between routine binary updates and mandatory database conversion determines downtime, rollback planning and data-integrity risk. The stabilised schema could reduce future upgrade complexity, but getting to 1.0 requires a tested migration. Performance claims are unusually well documented with reproducible benchmark configurations, yet remain maintainer measurements rather than independent proof that Stalwart is universally faster. Teams evaluating a move from Postfix/Dovecot also need to consider operational maturity, mail deliverability, security, client compatibility and support boundaries. ## Stable storage is the practical milestone The 1.0 database schema is intentionally finalised so later releases can upgrade in place rather than repeating disruptive migrations. This release itself is a breaking storage transition: the new server will not open an old store. The official migration tool reads the old store, copies data to a new one, supports incremental reruns and preserves IMAP UIDs and change history. The final cutover still needs planning; OAuth users must sign in again and search indexes rebuild. ## How existing installations move For v0.16 installations, update to 0.16.27, back up and test, then use stalwart-migrate with a new empty v1.0 store. For v0.15 or earlier and gradual moves, the documented migration proxy and Vandelay can route accounts between old and new servers. Clusters must now use a Redis-family in-memory coordinator; single-node installations can use a built-in local store. Configuration keys were also renamed or restructured. ## Performance and search changes are substantial but vendor-measured The maintainers rewrote mail-parser using SIMD/SWAR, tuned RocksDB, PostgreSQL, MySQL, FoundationDB and SQLite backends, and redesigned mailbox caches. A new full-text index supports phrase searches and text extraction from PDF, Office, OpenDocument, EPUB and RTF attachments. On matched Azure servers, Stalwart says it won 35 of 38 head-to-head Postfix/Dovecot tests. Benchmark scripts and raw data are published, but independent reproduction and comparisons across different production configurations are still needed. ## Security, protocols and integration caveats The release includes JMAP object metadata, IMAP METADATA, more OAuth/OIDC controls and post-quantum DKIM2 support. Early community upgrade reports noted a Bulwark Native OAuth client ID issue, with a webmail fix published and native update expected. Administrators should test every mail client, authentication flow and relay before switching production. Enterprise-only AI spam classification should not be presented as a Community-edition feature. ## Key details - Released October 26, 2026 as first stable Stalwart server version. - New on-disk schema requires migration; old stores cannot be opened by 1.0. - v0.16.27 is the prerequisite for stalwart-migrate; older versions use documented alternative migration path. - Cluster coordination now requires Redis; single-node has built-in local store. - New document-attachment full-text indexing and SIMD/SWAR parsing. - Vendor reports 35/38 benchmark wins against Postfix 3.11/Dovecot 2.4 with scripts and raw results published. - Post-quantum DKIM2, OAuth client metadata and finer scopes added. ## Builder takeaways - Back up mail and test an incremental migration from v0.16.27 before production cutover. - Do not replace a pre-1.0 binary without preparing a new v1.0 data store. - For clustered installations, plan Redis coordinator availability and failover. - Test OAuth clients, IMAP UIDs, mail delivery, search rebuild and rollback after migration. - Treat vendor performance numbers as a reproducible claim, not an independent guarantee. - Check Community versus Enterprise feature boundaries before choosing a deployment. ## What to watch - Independent performance replication against comparable Postfix/Dovecot configurations. - Migration and OAuth client compatibility reports from early adopters. - Whether future 1.x upgrades avoid data migrations as promised. ## Uncertainties - The 35/38 performance comparison is maintainer-run; no independent replication was established. - New stable-schema promises cannot yet be validated against future releases. - Early OAuth-client compatibility fixes may still be propagating across native clients. ## Sources - [Stalwart v1.0: The Fastest Mail Server on the Planet](https://stalw.art/blog/stalwart-1-0/) — Stalwart Labs · primary release and upgrade guide · 2026-10-26T00:00:00+13:00. Release changes, migration steps, benchmarking methodology, caveats and feature boundaries. - [Stalwart 1.0 Open-Source Mail Server Reaches Its First Stable Release](https://linuxiac.com/stalwart-1-0-open-source-mail-server-reaches-its-first-stable-release/) — Linuxiac · independent specialist reporting · 2026-10-26T00:00:00+13:00. Independent release coverage; not an independent benchmark. - [Stalwart v1.0 release announcement and support discussion](https://support.stalw.art/t/stalwart-v1-0-the-fastest-mail-server-on-the-planet/2034) — Stalwart Support · primary maintainer community · 2026-10-26T00:00:00+13:00. Maintainer's official announcement and discussion.