Hi Marlon, here's what PJ says about baking at high altitude: "Bakers working at high altitude should reduce the desired internal temperature of their breads by about 5°F, to account for water's lower boiling point." Judging by this, it seems like you might be able to go a little lower than 90C for your standard yeast white bread.  However, I would trust your own sense of when the bread seems done and look for these other signs that your bread is fully baked. 

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