Manual:$wgAutopromote

Details
This array contains criteria of automatic promotion. The syntax is: cond here may be: The latter has following syntax: There are 4 operands available: Condition can be written in two forms:
 * A single condition
 * A set of conditions
 * & (AND) — promote if user matches all conditions
 * | (OR) — promote if user matches any condition
 * ^ (XOR) — promote if user matches only one of two conditions
 * ! (NOT) &mdash; promote if user matches no conditions.

Possible conditions (extensions may add more through the AutopromoteCondition hook):
 * APCOND_EMAILCONFIRMED: email adress has been confirmed
 * APCOND_EDITCOUNT: minimal number of edits necessary
 * APCOND_AGE: minimal number of seconds since registration
 * APCOND_INGROUPS: list of groups the user must be in