There’s an article from IBM regarding connections from IBM Notes Traveler and IBM Verse clients to the corresponding server:

Beginning with January 1st, 2017, you HAVE TO use a secure connection via an official SSL certificate.

To be honest >> if someone still uses self-signed certificates, it’s a shame ;-).

In the coming months, IBM will be enhancing the IBM Verse for iOS, IBM Verse for Android, IBM Notes Traveler Companion and IBM Notes Traveler To Do mobile apps to require that a secure connection is used between the mobile app and the endpoint used for connecting to the IBM Traveler server.

This article provides the security requirements and step by step instructions for ensuring that your on-premises IBM Traveler environment has adequate connection security in place in order to support these updated apps. If your mobile users connect to IBM SmartCloud Notes for Traveler and the Verse Mobile service, these steps do not apply, since this environment is already prepared for these updates. If you have deployed an IBM Traveler server on your own premises, then please continue reading.

IMPORTANT: You must ensure that your IBM Verse Mobile and Traveler connections are secure and compliant with these requirements by January 1, 2017.

These requirements only apply to the server to which the Verse mobile apps are directly connecting. This may be the IBM Traveler server running on a Domino instance, or some other intermediate reverse proxy, such as an F5 or IBM Mobile Connect. When you enter the host name into your Verse mobile application to connect to your Traveler service, this host name represents the server with which the mobile app is directly connecting, and this is the connection that must be secured.  

You can read the complete instructions and requirements here:

http://www-01.ibm.com/support/docview.wss?uid=swg21989980&myns=swglotus&mynp=OCSSYRPW&mync=E&cm_sp=swglotus-_-OCSSYRPW-_-E