[ bug ] failed to resolve: could not find 'ServerCertVerified' in 'client'

[yonas]

Describe the bug

I'm trying to build https://github.com/stalwartlabs/stalwart but I ran into this error:

error[E0433]: failed to resolve: could not find 'ServerCertVerified' in 'client'

To Reproduce

$ git clone https://github.com/stalwartlabs/stalwart stalwart
$ cd stalwart
$ cargo build --release
...
error[E0433]: failed to resolve: could not find `ServerCertVerified` in `client`
   --> /home/yonas/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/rust-s3-0.35.1/src/request/tokio_backend.rs:75:28
    |
 75 |         Ok(rustls::client::ServerCertVerified::assertion())
    |                            ^^^^^^^^^^^^^^^^^^ could not find `ServerCertVerified` in `client`
    |
note: found an item that was configured out
   --> /home/yonas/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/rustls-0.21.12/src/lib.rs:436:65
    |
433 |     #[cfg(feature = "dangerous_configuration")]
    |           ----------------------------------- the item is gated behind the `dangerous_configuration` feature
...
436 |         CertificateTransparencyPolicy, HandshakeSignatureValid, ServerCertVerified,
    |                                                                 ^^^^^^^^^^^^^^^^^^

error[E0405]: cannot find trait `ServerCertVerifier` in module `rustls::client`
   --> /home/yonas/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/rust-s3-0.35.1/src/request/tokio_backend.rs:65:22
    |
 65 | impl rustls::client::ServerCertVerifier for NoCertificateVerification {
    |                      ^^^^^^^^^^^^^^^^^^ not found in `rustls::client`
    |
note: found an item that was configured out
   --> /home/yonas/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/rustls-0.21.12/src/lib.rs:437:9
    |
433 |     #[cfg(feature = "dangerous_configuration")]
    |           ----------------------------------- the item is gated behind the `dangerous_configuration` feature
...
437 |         ServerCertVerifier, WebPkiVerifier,
    |         ^^^^^^^^^^^^^^^^^^

error[E0412]: cannot find type `ServerCertVerified` in module `rustls::client`
   --> /home/yonas/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/rust-s3-0.35.1/src/request/tokio_backend.rs:74:33
    |
 74 |     ) -> Result<rustls::client::ServerCertVerified, rustls::Error> {
    |                                 ^^^^^^^^^^^^^^^^^^ not found in `rustls::client`
    |
note: found an item that was configured out
   --> /home/yonas/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/rustls-0.21.12/src/lib.rs:436:65
    |
433 |     #[cfg(feature = "dangerous_configuration")]
    |           ----------------------------------- the item is gated behind the `dangerous_configuration` feature
...
436 |         CertificateTransparencyPolicy, HandshakeSignatureValid, ServerCertVerified,

Environment

• Rust version: cargo 1.93.0-nightly (445fe4a68 2025-11-07), rustc 1.93.0-nightly (fb23dd3c6 2025-11-08)
• lib version: 0.35.1

Additional context OS: FreeBSD 14