Solo Loop and Braided Solo Loop bands are only compatible with Apple Watch SE and apple watch Series 4 or newer. The straps only fit the selected case size and are not compatible with other case sizes. For example, a size 5 for a 40mm housing does not work with a 44mm housing, and vice versa. Apple Watch Series 4, Series 5, and Series 6 come in 40mm and 44mm case sizes, so they're the same.
As long as you get the same size for the new Apple Watch, the existing bands should fit seamlessly. Getting a larger Apple Watch band basically ensures that it will work with previous wearables that were the larger size option of their respective generation. The Apple Watch Series 7 was one of many announcements made during Apple's “California Streaming” event, sharing the stage alongside iPhone 13 and 13 Pro, a new iPad Mini with USB-C charging, and more. Apple Watch Series 6 has an always-on display that's brighter than before, so you don't need to make that awkward wrist movement to see the time.
The watch comes in a new case size of 41 mm and 45 mm, moving away from the 40 mm and 44 mm size that has been the standard of the last generations of Apple Watch. While it may seem at first that Apple has unceremoniously eradicated support for all previous models, don't worry, it didn't. Recall that only four versions of the Apple Watch have the current dimensions, Series 4, Series 5, Series 6 and SE. With the Apple Watch coming in so many different case sizes, it's no wonder people get confused as to which of the different watch bands will fit the watch they have.
Until Apple makes a big design change with the Apple Watch, any band you have that works with the square shape will work. If you have an older Apple Watch Series 0, 1, 2 or 3, your bands should be for the 38mm or 42mm case. In case you didn't know, they're only compatible with Apple Watch SE, Series 4 and newer models. While I think the new straps will be labeled 41mm and 45mm, that doesn't mean they won't work with older watches.
For the 40mm and 41mm Apple Watch models, you can get individual loop bands in the size range of one to nine, while the 44mm and 45mm models work with band sizes four to 12.Weinbach's information that the new Apple Watch “will use different straps that won't be compatible with old watches” is open to interpretation, at best. So, that means Apple has to make new straps that are compatible with at least the SE or make straps that will only work for this year's models, once again unlikely to the point of being unthinkable.