It is well known that the Delaware General Corporation Law (DGCL) provides that a majority of the voting power of all stockholders entitled to vote is required for a Delaware corporation to take certain fundamental actions, including mergers, sales of all or substantially all of the corporate assets, and dissolutions. Included in this list are amendments to a corporation's charter, but a recent decision from the Delaware Court of Chancery is a reminder to corporations and practitioners alike that a class (or series) vote of stockholders can be, and often is, required under the DGCL, in addition to the general majority rule, when undertaking certain amendments to a corporate charter.
Source: More Than a Majority: Chancery Court Provides Rare Guidance on Charter Amendments