Microsoft will release Message Center – Weekly Digest Update in … September. You can see in Roadmap https://products.office.com/en-us/business/office-365-roadmap?featureid=18436.
Microsoft introduced Weekly Digest updates in the start of 2017.
Office 365 Message Center help organization to know what features are released and have the news of new applications have released or will be. With this mail digests the admins receives this notifications by email.
Next week will be released to all First Release admins.
In September will be released to all Tenants on Standard Release.
You can read more here https://support.office.com/en-us/article/Message-center-in-Office-365-38FB3333-BFCC-4340-A37B-DEDA509C2093?ui=en-US&rs=en-US&ad=US