generic associated types are unstable

[DineshSomalingam]

I'm a NOOB to Rust, but when I try to compile the code under examples router_v5, getting the below error. Would appreciate any help/hints in resolving this

error[E0658]: generic associated types are unstable
--> .cargo/registry/src/github.com-1ecc6299db9ec823/ntex-service-1.0.2/src/and_then.rs:41:5
|
41 | type Future<'f> = AndThenServiceResponse<'f, A, B, Req> where Self: 'f, Req: 'f;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: see issue #44265 rust-lang/rust#44265 for more information

[fafhrd91]

you need newer version of rust, min supported version of rust is 1.65