In ee91ccf for PHPLIB-539, an internal isAcknowledgedWriteConcern method was introduced to support error reporting for using a hint option with a FindAndModify operation (e.g. FindOneAndUpdate). That function currently requires a w value greater than 1 or a true j value, but fails to consider w=1 or a string value (e.g. "majority"). A string value will likely satisfy the comparison check, but it'd be preferable to explicitly handle strings here.

This came up while working on DRIVERS-1340, which will entail porting the isAcknowledgedWriteConcern to the Update, Delete, and BulkWrite operations.