Based on our record, WhenAvailable seems to be more popular. It has been mentiond 1 time since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
No pdfs involved but this site might be useful to you. They have a free and paid tier. When Available. Source: over 2 years ago
Zimbra - Zimbra is trusted by over 500 million users to increase productivity with a complete set of collaboration tools while maintaining total control over security and privacy.
When2Meet - When2meet helps you find the best time for a group to get together. It is a free survey tool that is quick and easy to use.
iRedMail - A fully fledged, free email server solution, an open source project (GPL v2).
Boomerang Calendar - Smart Calendar Assistant for Gmail | Boomerang Calendar
mailcow - An open source mailserver suite.
OnceHub - A scheduling and chatbot solution.