Can mobile phone iphone7P be reduced from ios11 to ios10.3.3 version now?

I want to test a bug on a ios10.3.3, but now the mobile phone is ios11, and now you can download ios10.3.3 firmware yourself, downgrade it with iTunes? Who can help me?

Can mobile phone iphone7P be reduced from ios11 to ios10.3.3 version now?
 
 
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