Neither I nor my special advisers have used the services in question for official business in the past 18 months.
With regard to the use of these services by officials in my Department, I am informed by the ICT unit that the Department does not support Slack which is a cloud based collaboration platform. However, some staff members may be accessing this without ICT support, as the website is not currently blocked. The Department provides alternatives to Slack which are supported. With regard to Signal, 22 staff members have downloaded the application to their Departmental phones.