The module is present in packages up to Match 2020

Instant messenger is a built-in text chat that lets your site members exchange quick messages with other users.

Sending messages via IM may be a paid service if you decide so. To make it a paid service, go to Payments > Services > Instant messenger, mark the service as ‘in use’ and indicate the cost and period.

In the user mode, the messenger is located in the right bottom corner under the title Chat with friends.

Under Modules > IM (Instant messenger settings) (/admin/im/index/) you can enable/disable the feature and limit a number of characters per message: