#Japt v2.0a0, 8 bytes

r\lÈ+c^H

Try it

##Explanation r :Replace \l :Regex /[a-z]/gi È :Pass each match X through a function + : Append c : The charcode of X ^ : Bitwise XORed H : With 32

Japt v2.0a0, 8 bytes

r\lÈ+c^H

Try it

Explanation

r            :Replace
 \l          :Regex /[a-z]/gi
   È         :Pass each match X through a function
    +        :  Append
    c        :  The charcode of X
     ^       :  Bitwise XORed
       H     :  With 32

#Japt v2.0a0, 8 bytes

r\lÈ+c^H

Try it

##Explanation r :Replace \l :Regex /[a-z]/gi È :Pass each X match through a function + : Append c : The charcode of X ^ : Bitwise XORed H : With 32

#Japt v2.0a0, 8 bytes

r\lÈ+c^H

Try it

##Explanation r :Replace \l :Regex /[a-z]/gi È :Pass each match X through a function + : Append c : The charcode of X ^ : Bitwise XORed H : With 32

#Japt v2.0a0, 8 bytes

r\lÈ+c^H

Try it

#Japt v2.0a0, 8 bytes

r\lÈ+c^H

Try it

##Explanation r :Replace \l :Regex /[a-z]/gi È :Pass each X match through a function + : Append c : The charcode of X ^ : Bitwise XORed H : With 32