Historical Rules · 1 May 2011
Rule 702.14d
Official source text from the 1 May 2011 Rules release
A permanent with protection can't be equipped by Equipment that have the stated quality or fortified by Fortifications that have the stated quality. Such Equipment or Fortifications become unattached from that permanent as a state-based action, but remain on the battlefield. (See rule 704, "State-Based Actions.")