Element
Element rebuilds its timeline with MVVM architecture while cutting legacy OS support in v1.12.28.
Comparison · Comms
Mailu vs Stalwart
A side-by-side editorial comparison of Mailu and Stalwart — release velocity, themes, recent moves, and the top alternatives to consider.
Mailu vs Stalwart: at a glance
What is Mailu?
Mailu ships one pinned release per issue, and most of them are Roundcube's.
The 2024.06 branch releases on demand: an issue or PR comes in, a pinned version goes out, and the changelog is one or two lines. Four of the six most recent releases are webmail-driven — three Roundcube bumps in this window alone, the latest to 1.6.18 clearing a TLS-configuration warning, an earlier one to 1.6.17 closing two CVEs. The remainder are Mailu's own code: an X-Forwarded-By header fix tied to a published advisory, sieve field escaping that repaired autoreplies and closed an injection path, and two admin-UI form flow corrections.
What is Stalwart?
Stalwart adds full SCIM v2 provisioning and 24-language calendar support as its standards coverage extends further than most commercial mail servers.
Stalwart is maintaining a weekly-or-faster release cadence, with alternating feature releases and dense bug-fix releases. The v0.16.20 release landed full SCIM v2 (Enterprise) including cursor-based pagination and the IPSIE lifecycle profile, conference links in calendar invites, and 24 new calendar interface translations. Below the feature line, the project is steadily closing correctness gaps across JMAP, CalDAV, IMAP, and MTA — many of them edge-case RFC compliance issues.
Mailu vs Stalwart: editorial side-by-side
Mailu
5.0COMMS
Mailu ships one pinned release per issue, and most of them are Roundcube's.
◆ Current state
The 2024.06 branch releases on demand: an issue or PR comes in, a pinned version goes out, and the changelog is one or two lines. Four of the six most recent releases are webmail-driven — three Roundcube bumps in this window alone, the latest to 1.6.18 clearing a TLS-configuration warning, an earlier one to 1.6.17 closing two CVEs. The remainder are Mailu's own code: an X-Forwarded-By header fix tied to a published advisory, sieve field escaping that repaired autoreplies and closed an injection path, and two admin-UI form flow corrections.
◆ Where it's heading
This is a maintenance branch behaving exactly as a maintenance branch should, and the pinned-version model is the product: operators get upstream security work packaged and tagged without tracking Roundcube themselves. The security items divide cleanly — most arrive from bundled components, a minority from Mailu's own code, and the project patches both on the same cadence. Nothing in this window suggests new capability is being developed on this branch.
◆ Prediction
Expect the next release to follow the same trigger: a Roundcube advisory or a client compatibility report producing a single-line changelog and a new pinned tag. Any feature work would be happening on the main version, which this feed does not cover.
Stalwart
6.3COMMS
Stalwart adds full SCIM v2 provisioning and 24-language calendar support as its standards coverage extends further than most commercial mail servers.
◆ Current state
Stalwart is maintaining a weekly-or-faster release cadence, with alternating feature releases and dense bug-fix releases. The v0.16.20 release landed full SCIM v2 (Enterprise) including cursor-based pagination and the IPSIE lifecycle profile, conference links in calendar invites, and 24 new calendar interface translations. Below the feature line, the project is steadily closing correctness gaps across JMAP, CalDAV, IMAP, and MTA — many of them edge-case RFC compliance issues.
◆ Where it's heading
Stalwart is building toward parity with commercial enterprise mail servers on identity federation and provisioning (SCIM v2, VAPID for web push, DMARCbis/DKIM2 already landed). The pace of RFC implementation is unusually aggressive for an open-source project; the combination of JMAP, CalDAV, IMAP UIDONLY/UIDBATCHES, and SCIM v2 positions it as a viable self-hosted alternative for organizations that need standards compliance without vendor lock-in.
◆ Prediction
WebAuthn/passkey-based authentication and improved multi-tenant administration tooling are the most likely next capability additions, given the current trajectory toward enterprise identity management.
Alternatives to Mailu and Stalwart
Other Comms products tracked by Sparkpulse, ranked by recent ship velocity. Each card links to a full editorial trajectory and lets you pivot into a head-to-head comparison with either Mailu or Stalwart.
Superhuman
Superhuman rebuilt its mobile apps and wired every inbox into AI assistants — the email client is becoming a suite.
Chatwoot
Chatwoot is building an AI-first support platform, with Captain gaining audience targeting and macro automation reaching the keyboard-native workflow.
Signal Desktop
Signal adds granular notification controls: badge content, muted threads, restore defaults
Zoho Cliq
Zoho Cliq 7.0 bets on AI conversation summaries and Neat hardware to close the gap with enterprise messaging platforms
Krisp
Krisp adds deepfake detection and expands Voice Translation as its Call Center AI platform deepens enterprise compliance tools.
See all Mailu alternatives → · See all Stalwart alternatives →
Recent activity from Mailu and Stalwart
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 10d agoStalwartv0.16.21
- 17d agoStalwartv0.16.20 ⚡
- 23d agoStalwartv0.16.19
- 1mo agoStalwartv0.16.18
- 1mo agoMailuRoundcube 1.6.18 bump clears a TLS-config warning
- 1mo agoStalwartv0.16.17
- 1mo agoStalwartv0.16.16
- 1mo agoMailuAutoconfig fix for modern K-9 Mail
- 1mo agoMailuRoundcube 1.6.17 closes two CVEs
- 2mo agoMailuSets X-Forwarded-By in response to a GHSA advisory
- 2mo agoMailuAdmin UI keeps form values on failed submit
- 2mo agoMailuEscapes sieve fields, fixing autoreplies with special characters
Frequently asked questions
What is the difference between Mailu and Stalwart?
They serve adjacent needs but don't currently overlap on shipped themes. Stalwart is currently shipping more aggressively (velocity 6.3 vs 5.0), with 1 editorial sparks in the last 30 days against 0. See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.
Is Mailu better than Stalwart?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Stalwart is currently shipping more aggressively (velocity 6.3 vs 5.0), with 1 editorial sparks in the last 30 days against 0. For your specific use case, the alternatives sections above list other Comms products to evaluate alongside.
What are the best alternatives to Mailu?
Top Mailu alternatives in Comms are ranked by recent ship velocity. Browse the "Mailu alternatives" section above for the current picks, or visit /alternatives/mailu for the full list with editorial commentary on each.
What are the best alternatives to Stalwart?
Top Stalwart alternatives in Comms are ranked by recent ship velocity. Browse the "Stalwart alternatives" section above for the current picks, or visit /alternatives/stalwart for the full list with editorial commentary on each.