Boot upper
FIG. 1 is a right side elevation view of a boot upper showing my new design; 
     FIG. 2 is a top plan view thereof; 
     FIG. 3 is a left side elevational view thereof; 
     FIG. 4 is a rear elevational view thereof; and, 
     FIG. 5 is a front elevational view thereof. 
     The broken line showing of a shoe sole and laces in FIGS. 1-5 is for illustrative purposes only and forms no part of the claimed design.