Postmark
Postmark adds its own SOC 2 Type 2 report to a run of security work.
Comparison · Comms
Gromox vs mailcow
A side-by-side editorial comparison of Gromox and mailcow — release velocity, themes, recent moves, and the top alternatives to consider.
Gromox vs mailcow: at a glance
What is Gromox?
Gromox 3.13 adds scripts to move Exchange-for-All systems onto it.
Gromox ships a numbered release roughly monthly. 3.13 adds scripts to convert E4A systems to Gromox, full two-way sync of IMAP keywords with MAPI categories, multi-message vCard export and audit logging in emsmdb and zcore, and fixes an EWS gap where any user could answer, alter or move meeting requests in other mailboxes. 3.12 moved MAPI-to-internet conversion onto VMIME with RFC 2231 filenames; 3.11 added IMAP FETCH BINARY and Sent Items copies for send-as and send-on-behalf on shared mailboxes.
What is mailcow?
mailcow's November release patches an admin RCE and reworks sync jobs.
mailcow ships named monthly releases with lettered revisions, mostly to pull in upstream security fixes for SOGo, Nginx, Redis, Unbound and Rspamd. The November release goes further: it fixes a remote code execution flaw reachable by admins and domain admins, adds mailbox groups, and reworks imapsync so sync jobs reference a separate source. It also caps request bodies at 64 MB, which breaks large SOGo and ActiveSync mail unless NGINX_MAX_BODY_SIZE is raised.
Gromox vs mailcow: editorial side-by-side
Gromox
2.5COMMS
Gromox 3.13 adds scripts to move Exchange-for-All systems onto it.
◆ Current state
Gromox ships a numbered release roughly monthly. 3.13 adds scripts to convert E4A systems to Gromox, full two-way sync of IMAP keywords with MAPI categories, multi-message vCard export and audit logging in emsmdb and zcore, and fixes an EWS gap where any user could answer, alter or move meeting requests in other mailboxes. 3.12 moved MAPI-to-internet conversion onto VMIME with RFC 2231 filenames; 3.11 added IMAP FETCH BINARY and Sent Items copies for send-as and send-on-behalf on shared mailboxes.
◆ Where it's heading
The project keeps completing Exchange behaviour for clients that expect it, now including shared-mailbox Sent Items and meeting handling that matches Exchange. 3.13's conversion scripts and audit logging point at migration and compliance as the adoption path, alongside the IMAP work that has run since 3.8. Permission checks on EWS calendar operations show the protocol surface now gets security review, not only coverage.
◆ Prediction
Expect more EWS permission and behaviour corrections and continued IMAP4rev2 coverage; the E4A scripts suggest further migration tooling from other groupware.
mailcow
5.0COMMS
mailcow's November release patches an admin RCE and reworks sync jobs.
◆ Current state
mailcow ships named monthly releases with lettered revisions, mostly to pull in upstream security fixes for SOGo, Nginx, Redis, Unbound and Rspamd. The November release goes further: it fixes a remote code execution flaw reachable by admins and domain admins, adds mailbox groups, and reworks imapsync so sync jobs reference a separate source. It also caps request bodies at 64 MB, which breaks large SOGo and ActiveSync mail unless NGINX_MAX_BODY_SIZE is raised.
◆ Where it's heading
The monthly security cadence holds, but recent releases carry more of mailcow's own features and API changes alongside the upstream bumps. Breaking changes now come with explicit migration steps, which suggests the API is being cleaned up for integrators.
◆ Prediction
Expect the promised RCE advisory details next week and a lettered revision within weeks to address fallout from the sync job API and body-size changes.
Alternatives to Gromox and mailcow
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 Gromox or mailcow.
Element X Android
Element X Android turns on multi-select forwarding and better search in v26.11.0.
Fonoster
Fonoster lets voice agents pick Anthropic, Google or Groq models and record calls with one switch.
Salesmsg
Salesmsg's Sherpa AI now sends replies and builds broadcasts on request, with approval first.
Proton Bridge
Proton Bridge v3.27.2 adds support for the oo7 keyring on Linux.
Netcore Cloud
Netcore keeps publishing unified-platform explainers with no product release.
See all Gromox alternatives → · See all mailcow alternatives →
Recent activity from Gromox and mailcow
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 4d agomailcowMoovember 2026: admin RCE fix, mailbox groups, imapsync rework
- 11d agoGromoxGromox 3.13
- 19d agomailcow🎃🐮 Mooctober 2026 | Security Update: PHP 8.2.35, SOGo 5.12.12 & Nginx 1.30.6
- 1mo agomailcow2026-09a: Rspamd 4.2.1 and postfix-tlspol bumps
- 1mo agoGromoxGromox 3.12
- 1mo agoGromoxGromox 3.11
- 1mo agomailcow🍂🐮 Mootember 2026 | Unbound 1.26.1, SOGo 5.12.11 & Redis 7.4.11
- 2mo agoGromox3.10 makes IMAP flags durable and teaches EWS Outlook for Mac's drafts
- 2mo agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3 - Revision B
- 3mo agomailcow🏖️🐮 Mooly 2026 | Postfix 3.10.12, Rspamd 4.1.0 & Nginx 1.30.3 - Revision A
- 3mo agoGromox3.9 makes room bookings and EWS meetings properly actionable
- 4mo agoGromox3.8 splits the Information Store per store and extends IMAP
Frequently asked questions
What is the difference between Gromox and mailcow?
They serve adjacent needs but don't currently overlap on shipped themes. mailcow is currently shipping more aggressively (velocity 5.0 vs 2.5), with 0 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 Gromox better than mailcow?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. mailcow is currently shipping more aggressively (velocity 5.0 vs 2.5), with 0 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 Gromox?
Top Gromox alternatives in Comms are ranked by recent ship velocity. Browse the "Gromox alternatives" section above for the current picks, or visit /alternatives/gromox for the full list with editorial commentary on each.
What are the best alternatives to mailcow?
Top mailcow alternatives in Comms are ranked by recent ship velocity. Browse the "mailcow alternatives" section above for the current picks, or visit /alternatives/mailcow for the full list with editorial commentary on each.