diff --git a/Cargo.lock b/Cargo.lock
index 59c9036d5..0bba9e3bb 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -165,9 +165,9 @@ dependencies = [
 
 [[package]]
 name = "async-imap"
-version = "0.3.3"
+version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c082ecb52ec3af0aa61d4314750086134ef9c7521edb41f7981c0f45650c0c7b"
+checksum = "caadebe62f5ad78d6418a47a86b5b84439a52bdd5c893e55a5c81974da111455"
 dependencies = [
  "async-native-tls",
  "async-std",
diff --git a/Cargo.toml b/Cargo.toml
index 50617bf30..6d200648b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -23,7 +23,7 @@ num-traits = "0.2.6"
 async-smtp = "0.3"
 email = { git = "https://github.com/deltachat/rust-email", branch = "master" }
 lettre_email = { git = "https://github.com/deltachat/lettre", branch = "master" }
-async-imap = "0.3.1"
+async-imap = "0.4.0"
 async-native-tls = { version = "0.3.3" }
 async-std = { version = "1.6.1", features = ["unstable"] }
 base64 = "0.12"
diff --git a/src/imap/client.rs b/src/imap/client.rs
index 2ee8165d1..d313db80b 100644
--- a/src/imap/client.rs
+++ b/src/imap/client.rs
@@ -56,7 +56,7 @@ impl Client {
     pub async fn authenticate<A: async_imap::Authenticator, S: AsRef<str>>(
         self,
         auth_type: S,
-        authenticator: &A,
+        authenticator: A,
     ) -> std::result::Result<Session, (ImapError, Self)> {
         let Client { inner, is_secure } = self;
         let session =
@@ -85,9 +85,6 @@ impl Client {
         let tls_stream: Box<dyn SessionStream> =
             Box::new(tls.connect(domain.as_ref(), stream).await?);
         let mut client = ImapClient::new(tls_stream);
-        if std::env::var(crate::DCC_IMAP_DEBUG).is_ok() {
-            client.debug = true;
-        }
 
         let _greeting = client
             .read_response()
@@ -104,9 +101,6 @@ impl Client {
         let stream: Box<dyn SessionStream> = Box::new(TcpStream::connect(addr).await?);
 
         let mut client = ImapClient::new(stream);
-        if std::env::var(crate::DCC_IMAP_DEBUG).is_ok() {
-            client.debug = true;
-        }
         let _greeting = client
             .read_response()
             .await
diff --git a/src/imap/mod.rs b/src/imap/mod.rs
index ef4ea8b09..384c76111 100644
--- a/src/imap/mod.rs
+++ b/src/imap/mod.rs
@@ -129,7 +129,7 @@ struct OAuth2 {
 impl async_imap::Authenticator for OAuth2 {
     type Response = String;
 
-    fn process(&self, _data: &[u8]) -> Self::Response {
+    fn process(&mut self, _data: &[u8]) -> Self::Response {
         format!(
             "user={}\x01auth=Bearer {}\x01\x01",
             self.user, self.access_token
@@ -262,7 +262,7 @@ impl Imap {
                             user: imap_user.into(),
                             access_token: token,
                         };
-                        client.authenticate("XOAUTH2", &auth).await
+                        client.authenticate("XOAUTH2", auth).await
                     } else {
                         return Err(Error::OauthError);
                     }