Is it true that it is forbidden to turn a shoe upside down so that its sole faces the sky?

Some people believe that turning over footwear (so that its sole faces upwards) is forbidden (haram) and that it must be immediately corrected. However, there is no evidence for this belief, and we are not aware of any scholar who has deemed it reprehensible (makruh) or forbidden. Sheikh Ibn Uthaymeen mentioned that this belief is unfounded.