- https://addons.thunderbird.net/en-US/thunderbird/addon/owl-for-exchange/ – “Allows you to use your Exchange email accounts that use Outlook Web Access (OWA) with Thunderbird”
- https://www.beonex.com/owl/
- https://addons.thunderbird.net/en-US/thunderbird/addon/exquilla-exchange-web-services/ – “Thunderbird email accounts connecting to Microsoft Exchange Web Services”
- https://www.exquilla.com
- https://addons.thunderbird.net/en-US/thunderbird/user/owl-beonex/
- https://www.beonex.com/owl/ – homepage of developers of both (owl and exqilla): Beonex GmbH, Wiesbaden
- https://exquilla.zendesk.com/hc/en-us/articles/360030845251-What-is-the-difference-between-Owl-and-ExQuilla-Which-one-should-I-use- – comparison – basically: ExQuilla is based on some technology deprecated by Thunderbird, owl is the product to go for