PHP

The module has been tested with PHP 5.2.6.

It is unlikely to work with versions prior to 5.2 and will categorically NOT work with any version of PHP 4.

MySQL

The module has been tested with MySQL 5.0.67

It has not been tested using any other database engine, but I would imagine some modifications would be required.

Drupal

Native 6, tested on 6.12 through to 6.19

If you can add further information to this section, please let me know by email and I will update accordingly. All my work has been completed using the Linux Suse 11.1 environment; as a consequence I can neither vouch for the module working under Windows, nor can I offer any specific Windows OS support. 

Tested Caldav Servers

The module has been tested on the following caldav servers, and is proven to be functioning correctly:

OSAF Cosmo Server 1.1.0

OSAF  Chandler Hub Version 1.1

DAViCal

Google Calendars

Note: this uses HTTP 1.1 protocol and not caldav. Further details in the FAQ.

Untested Caldav Servers

The module should work with the following servers but is currently untested. Please report any success or failures you may have. 

Scalix

Zimbra

Note: It appears by reading the Zimbra documentation that caldav is not supported, but HTTP 1.1 is. So on that basis, anyone using the extension with Zimbra should configure the collection as "Google Calendars".

Servers Not Supported

There are no plans to include MS Exchange support.