With the help of your stakeholder group and test volunteers, you should be able to gauge how much impact the hub will have on your audience. Compile any information on processes or workflows that would be affected by the change. Consider talking points for managers in team meetings or other regular employee communication channels. Send communications a few days to a week in advance.
Your communication can include points such as:
Benefits and uses for the Hub that solve employee or manager problems.
Dates for changes.
Before and after images of functionality changes.
Contact information for questions or feedback.
Required steps by the employee to prepare, if there are any.