Supposedly there is a big announcement being made next month. Some rumors on what it can be is:

Mesa shutting down

Mesa merging with commute air

United buys Mesa

Mesa selling all CRJs in one go, and having only an all ejet fleet

Aviate removing Mesa, and United making Mesa being the only regional where there will be a 100% guarantee flow to United in order by seniority number

Can be one, none, or a combination of these.