Along with a Thunderbird <> HubSpot Sales Extension plugin, CalDAV and CardDAV Support for synching calendar and contacts data would be one of the most valuable improvements to HubSpot for us. We’re not relying on either Microsoft or Gmail tools but on self-hosted mail servers and Nextcloud for groupware and calendar features. Supporting free, open-source tools and standards like CalDAV, CardDAV and Thunderbird would make HubSpot an even better CRM solution, especially for small businesses and startups that either can’t afford business solutions from big players like Microsoft and Google from the beginning or do not want to rely on these companies for privacy or whatever other reasons.