From the AOPA Air Traffice Services Team:
The modification reduces the Class B shelf floors (as noted in red in the attached depiction) along with an expansion of the cutout around Stanton Airfield (SYN). We want to encourage the flying public to become familiar with the changes and plan accordingly. As I am sure you are well aware, MSP Class B airspace area falls on three Sectional Charts, Twin Cities, Omaha and Green Bay, which do not all align with the effective date of this modification. In an attempt to mitigate this issue, the FAA has published two safety alerts and modified the Green Bay VFR chart. The current edition of the Green Bay Sectional Chart will remain effective until January 9, 2014, with the next edition effective from January 9, 2014 to May 29, 2014. However, the Omaha Sectional Chart, effective 6 February 2014 will not depict the modification for 29 days. AOPA urges pilots to refer to the Aeronautical Chart Bulletins section of the Airport/Facility Directory for updated information regarding major changes in aeronautical information that have occurred since the last chart publication date.
Additional details are part of a previous AOPA article linked below:
Omaha VFR Chart, Safety Alert:
Green Bay VFR Chart, Safety Alert: