"My future boots are going to be blue."
Translation:Mes futures bottes vont être bleues.
Because the engine has 'vont etre' for 'going to be' and 'seront' for 'will be'. I'm definitely not an expert but in normal usage i think they'd be pretty interchangeable. Still useful to know the difference tho!
Mes prochaines bottes = my next boots.
The adjective taught here is "futur(e)(s)".
The answer displaying here is mes futures bottes vont être bleues, however mes prochaines bottes vont être bleues means the same thing. Did you remember to pluralise futures?