Rspamd
Rspamd 4.3 fixes SPF evaluation order and rejects weak DKIM keys, with results that change.
Comparison · Comms
Roundcube vs Slack
A side-by-side editorial comparison of Roundcube and Slack — release velocity, themes, recent moves, and the top alternatives to consider.
Roundcube vs Slack: at a glance
What is Roundcube?
Roundcube patches its Sieve filters and CSRF checks in a sixth paired security release
Roundcube shipped 1.7.6 and 1.6.21 on 9 November, three weeks after 1.7.5 and 1.6.20, again as an identical security pair. This round centres on the managesieve filter plugin (two script-injection paths and destructive actions triggerable cross-site via GET), plus CSRF bypasses, an open redirect, an SSRF bypass via nip.io and sslip.io hostnames and a disabled_actions bypass.
What is Slack?
Slack now hosts any A2A agent without Slack-specific code.
Slack's developer channel is almost all agent plumbing. On 10 November Slack became an A2A (Agent2Agent) client: a team hosts its own agent, publishes an Agent Card, and Slack calls it when people talk to it, with no request URL, event handling or Slack-specific logic. This follows Slackbot skills managed through Web API methods, a Slack CLI that points coding agents to the Slack MCP server, and a new requirement that Work Objects embeds allow the slack-mcps.com frame ancestor.
Roundcube vs Slack: editorial side-by-side
Roundcube
5.0COMMS
Roundcube patches its Sieve filters and CSRF checks in a sixth paired security release
◆ Current state
Roundcube shipped 1.7.6 and 1.6.21 on 9 November, three weeks after 1.7.5 and 1.6.20, again as an identical security pair. This round centres on the managesieve filter plugin (two script-injection paths and destructive actions triggerable cross-site via GET), plus CSRF bypasses, an open redirect, an SSRF bypass via nip.io and sslip.io hostnames and a disabled_actions bypass.
◆ Where it's heading
Security releases now arrive every three to five weeks, each with a dozen or more externally reported fixes, and the same research group is behind many of them. The project is in a sustained audit phase, and both branches move together every time.
◆ Prediction
Another paired 1.7.x and 1.6.x security release within about a month is the most likely next entry, given the cadence since June.
Slack
6.3COMMSCOLLAB
Slack now hosts any A2A agent without Slack-specific code.
◆ Current state
Slack's developer channel is almost all agent plumbing. On 10 November Slack became an A2A (Agent2Agent) client: a team hosts its own agent, publishes an Agent Card, and Slack calls it when people talk to it, with no request URL, event handling or Slack-specific logic. This follows Slackbot skills managed through Web API methods, a Slack CLI that points coding agents to the Slack MCP server, and a new requirement that Work Objects embeds allow the slack-mcps.com frame ancestor.
◆ Where it's heading
Slack is lowering the cost of putting outside agents in front of its users: first skills as code, then MCP pointers for coding agents, now a standard protocol in place of the Slack app model for agents. The platform is positioning itself as the place where agents built anywhere meet the people who use them.
◆ Prediction
Expect more A2A follow-ups, such as agents appearing in Slackbot or skills surfaces and richer Agent Card features, given how fast the agent releases have stacked up since October.
Alternatives to Roundcube and Slack
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 Roundcube or Slack.
Twilio
Twilio's voice AI stops cutting callers off mid-sentence, using its own turn-taking model.
Salesmsg
Salesmsg adds call-back requests and a one-click Emergency Stop for all outbound texts.
Element
Element 1.12.35 follows the call picture-in-picture release with one desktop storage fix.
Krisp
Krisp moves call transcripts and live captions to cloud transcription in KrispCX 2.84.4.
Misskey
Misskey 2026.11 ships: a leaner start script, and Node.js 22 no longer boots.
See all Roundcube alternatives → · See all Slack alternatives →
Recent activity from Roundcube and Slack
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 4d agoSlackBring your A2A agents to Slack ⚡
- 4d agoRoundcubeRoundcube Webmail 1.7.6
- 4d agoRoundcubeRoundcube Webmail 1.6.21
- 8d agoSlackWork Objects embeds require the slack-mcps.com frame ancestor
- 10d agoSlackSlack CLI 4.13 tells coding agents about Slack MCP and Skills
- 10d agoSlackSlack Skills Plugin installs in Claude Code from its own marketplace
- 12d agoSlackUpdated low-usage submission criteria for Slack Marketplace apps
- 15d agoSlackSlack CLI 4.12.0, the fourth CLI release in October
- 26d agoRoundcubeRoundcube Webmail 1.7.5
- 26d agoRoundcubeRoundcube Webmail 1.6.20
- 2mo agoRoundcubeRoundcube Webmail 1.7.4
- 2mo agoRoundcubeRoundcube Webmail 1.6.19
Frequently asked questions
What is the difference between Roundcube and Slack?
They serve adjacent needs but don't currently overlap on shipped themes. Slack 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 Roundcube better than Slack?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Slack 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 Roundcube?
Top Roundcube alternatives in Comms are ranked by recent ship velocity. Browse the "Roundcube alternatives" section above for the current picks, or visit /alternatives/roundcube for the full list with editorial commentary on each.
What are the best alternatives to Slack?
Top Slack alternatives in Comms are ranked by recent ship velocity. Browse the "Slack alternatives" section above for the current picks, or visit /alternatives/slack for the full list with editorial commentary on each.