Kerio Connect is described as 'makes email, calendars, contacts and task management easy and affordable. With Kerio Connect, you have immediate, secure access to your communications anytime, anywhere, on any device - without complexity or expensive overhead' and is an app in the Office & Productivity category. There are more than 10 alternatives to Kerio Connect for a variety of platforms, including Online / Web-based, Windows, Linux, Mac and Self-Hosted solutions. The best alternative is Zoho. It's not free, so if you're looking for a free alternative, you could try Zimbra Collaboration Suite or hMail Server. Other great apps like Kerio Connect are Google Workspace (Paid), Microsoft 365 (Paid), Kolab Now (Paid, Open Source) and Kopano (Freemium, Open Source).
Zimbra Collaboration is an open, secure collaboration tool for email, calendaring, tasks and more. With the most innovative web application available today, Zimbra boosts the productivity of users on any desktop and dramatically reduces TCO compared to legacy platform vendors.
Nextcloud is the most deployed on-premises file share and collaboration platform. Access & collaborate across your devices. As fully on-premises solution, Nextcloud Hub provides the benefits of online collaboration without the compliance and security risks.
Microsoft Exchange Server is a messaging and collaborative software product developed by Microsoft. It is part of the Microsoft Servers line of server products and is widely used by enterprises using Microsoft infrastructure solutions.
Axigen provides a multi-tenant, fully integrated, multi-platform, all-in-one email, calendaring and collaboration messaging solution. It grants extensive branding options and is localized in over 29 languages (including right-to-left writing mode).