Hello Katie-Louise!
Welcome to planDisney! I see that you plan on visiting this July and I'm not sure if you experienced a Florida summer yet but it is quite an experience. The heat and humidity affect my Park touring strategy greatly as it will now involve me transporting myself from one air-conditioned location to another as quickly as possible.
Katie-Louise, I'm not sure where you heard such news but it is absolutely not true. Walt Disney World Resort will continue to provide air-conditioning in all of the indoor areas that it always has. The Guests, Cast Members, rides, attractions, and merchandise need stable environments to function and remain in good condition. Florida is a subtropical environment and while it feels lovely to this perpetually cold New Yorker, even I have my limits when my sweat pours out of every pore. Katie-Louise, please know that you will still enjoy the sweet sweet conditioned air throughout Walt Disney World Resort such that you may even find yourself needing a light cardigan.
One of my favorite attractions to enjoy as well as cool down in is
Walt Disney's Carousel of Progress. Another cool-down spot for my family is
Mickey's PhilharMagic which has a little water spritz included as well.
I hope this was helpful and if you ever need the truth, you know we are here for you!
Happy Planning!
-Nimmy