The execution and validity of a lost will must be proved by two witnesses, who need not testify as the contents of the will.  The contents of the will must be proved by clear and convincing evidence.   Estate of Wilner, 636 Pa. 277, 142 A. 3d 796, No. 136 MAP 2014 (7/19/2016), rev’g 92 A.3d 1201 (Pa. Super. 2014).