OpenPaaS and WikiSuite have some similarities. This page is to explain the differences and rationale of choices. You likely will be interested in the other alternatives to WikiSuite.
OpenPaaS is licensed AGPL with the following clause:
In accordance with Section 7 and subsection (b) of the GNU Affero General Public License version 3, these Appropriate Legal Notices consist in the display of the Signature Notice “OpenPaaS is powered by Linagora.” for any and all type of outbound messages (e.g. e-mail and meeting requests). Retaining this Signature Notice in any and all free and Open Source versions of OpenPaaS is mandatory notwhistanding any other terms and conditions. These Signature Notices can be freely translated and replaced by any notice of strictly identical meaning in another language according to localization of the software, provided such notice clearly displays the words “OpenPaaS” and “Linagora”. Regardless of the notice language, the Logo/words "OpenPaaS" must be a clickable hypertext link that leads directly to the Internet URL http://open-paas.org. The Logo/word "Linagora" must be a clickable hypertext link that leads directly to the Internet URL http://www.linagora.com.
The licensing for WikiSuite is less restrictive. The components in WikiSuite all have licences that are OSI compliant
but none have network restrictions like AGPL.
And about the clause to prohibit removal of “OpenPaaS is powered by Linagora.” on "all type of outbound messages (e.g. e-mail and meeting requests)": There is nothing like this in the WikiSuite ecosystem. You can change the user visible messages to anything you want. We hope you will choose to promote the WikiSuite project in any way that makes sense to you, and forcing such messages is something end users won't appreciate. It also reinforces the perception of "Single Vendor Open Source". It's much better to do everything possible to have Community Open Source.