diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index dbd77e8720..ab63e5b162 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -103,9 +103,9 @@ jobs:
           - os: macos-latest
             rust: 1.83.0
 
-          # Minimum Supported Rust Version = 1.81.0
+          # Minimum Supported Rust Version = 1.77.0
           - os: ubuntu-latest
-            rust: 1.81.0
+            rust: 1.77.0
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
diff --git a/Cargo.toml b/Cargo.toml
index 1a5f561966..dbf0eb202d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,7 +3,7 @@ name = "deltachat"
 version = "1.152.0"
 edition = "2021"
 license = "MPL-2.0"
-rust-version = "1.81"
+rust-version = "1.77"
 repository = "https://github.com/deltachat/deltachat-core-rust"
 
 [profile.dev]
diff --git a/src/chat.rs b/src/chat.rs
index 320fffb854..437dbff4ef 100644
--- a/src/chat.rs
+++ b/src/chat.rs
@@ -312,7 +312,7 @@ impl ChatId {
 
     /// Create a group or mailinglist raw database record with the given parameters.
     /// The function does not add SELF nor checks if the record already exists.
-    #[expect(clippy::too_many_arguments)]
+    #[allow(clippy::too_many_arguments)]
     pub(crate) async fn create_multiuser_record(
         context: &Context,
         chattype: Chattype,
@@ -4444,7 +4444,7 @@ pub(crate) async fn delete_and_reset_all_device_msgs(context: &Context) -> Resul
 ///
 /// For example, it can be a message showing that a member was added to a group.
 /// Doesn't fail if the chat doesn't exist.
-#[expect(clippy::too_many_arguments)]
+#[allow(clippy::too_many_arguments)]
 pub(crate) async fn add_info_msg_with_cmd(
     context: &Context,
     chat_id: ChatId,
diff --git a/src/contact.rs b/src/contact.rs
index 61ad7db1f4..6ce4ecfa9f 100644
--- a/src/contact.rs
+++ b/src/contact.rs
@@ -805,6 +805,7 @@ impl Contact {
         }
 
         let mut name = sanitize_name(name);
+        #[allow(clippy::collapsible_if)]
         if origin <= Origin::OutgoingTo {
             // The user may accidentally have written to a "noreply" address with another MUA:
             if addr.contains("noreply")
diff --git a/src/imap.rs b/src/imap.rs
index cbf241071d..50a159b387 100644
--- a/src/imap.rs
+++ b/src/imap.rs
@@ -1301,7 +1301,7 @@ impl Session {
     /// Returns the last UID fetched successfully and the info about each downloaded message.
     /// If the message is incorrect or there is a failure to write a message to the database,
     /// it is skipped and the error is logged.
-    #[expect(clippy::too_many_arguments)]
+    #[allow(clippy::too_many_arguments)]
     pub(crate) async fn fetch_many_msgs(
         &mut self,
         context: &Context,
@@ -2689,6 +2689,7 @@ mod tests {
         }
     }
 
+    #[allow(clippy::too_many_arguments)]
     async fn check_target_folder_combination(
         folder: &str,
         mvbox_move: bool,
diff --git a/src/mimefactory.rs b/src/mimefactory.rs
index 8780073041..8f5f66f015 100644
--- a/src/mimefactory.rs
+++ b/src/mimefactory.rs
@@ -1047,6 +1047,7 @@ impl MimeFactory {
         part.body(text)
     }
 
+    #[allow(clippy::cognitive_complexity)]
     async fn render_message(
         &mut self,
         context: &Context,
diff --git a/src/mimeparser.rs b/src/mimeparser.rs
index 4eb80b4d9e..b8c2358ba9 100644
--- a/src/mimeparser.rs
+++ b/src/mimeparser.rs
@@ -1279,7 +1279,7 @@ impl MimeMessage {
         Ok(self.parts.len() > old_part_count)
     }
 
-    #[expect(clippy::too_many_arguments)]
+    #[allow(clippy::too_many_arguments)]
     async fn do_add_single_file_part(
         &mut self,
         context: &Context,
diff --git a/src/param.rs b/src/param.rs
index f1d3cb7619..d83beef6b7 100644
--- a/src/param.rs
+++ b/src/param.rs
@@ -371,6 +371,7 @@ impl Params {
     /// Note that in the [ParamsFile::FsPath] case the blob can be
     /// created without copying if the path already refers to a valid
     /// blob.  If so a [BlobObject] will be returned.
+    #[allow(clippy::needless_lifetimes)]
     pub async fn get_blob<'a>(
         &self,
         key: Param,
diff --git a/src/pgp.rs b/src/pgp.rs
index 804d520c09..f729237d99 100644
--- a/src/pgp.rs
+++ b/src/pgp.rs
@@ -21,9 +21,11 @@ use tokio::runtime::Handle;
 use crate::constants::KeyGenType;
 use crate::key::{DcKey, Fingerprint};
 
+#[allow(missing_docs)]
 #[cfg(test)]
 pub(crate) const HEADER_AUTOCRYPT: &str = "autocrypt-prefer-encrypt";
 
+#[allow(missing_docs)]
 pub const HEADER_SETUPCODE: &str = "passphrase-begin";
 
 /// Preferred symmetric encryption algorithm.
diff --git a/src/quota.rs b/src/quota.rs
index a0e8df346b..0070a76ca3 100644
--- a/src/quota.rs
+++ b/src/quota.rs
@@ -187,7 +187,7 @@ mod tests {
         Ok(())
     }
 
-    #[expect(clippy::assertions_on_constants)]
+    #[allow(clippy::assertions_on_constants)]
     #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
     async fn test_quota_thresholds() -> anyhow::Result<()> {
         assert!(QUOTA_ALLCLEAR_PERCENTAGE > 50);
diff --git a/src/receive_imf.rs b/src/receive_imf.rs
index 439731e9b5..3a58c5473b 100644
--- a/src/receive_imf.rs
+++ b/src/receive_imf.rs
@@ -158,7 +158,7 @@ async fn insert_tombstone(context: &Context, rfc724_mid: &str) -> Result<MsgId>
 /// If `is_partial_download` is set, it contains the full message size in bytes.
 /// Do not confuse that with `replace_msg_id` that will be set when the full message is loaded
 /// later.
-#[expect(clippy::too_many_arguments)]
+#[allow(clippy::too_many_arguments)]
 pub(crate) async fn receive_imf_inner(
     context: &Context,
     folder: &str,
@@ -679,7 +679,7 @@ pub async fn from_field_to_contact_id(
 /// Creates a `ReceivedMsg` from given parts which might consist of
 /// multiple messages (if there are multiple attachments).
 /// Every entry in `mime_parser.parts` produces a new row in the `msgs` table.
-#[expect(clippy::too_many_arguments)]
+#[allow(clippy::too_many_arguments, clippy::cognitive_complexity)]
 async fn add_parts(
     context: &Context,
     mime_parser: &mut MimeMessage,
@@ -1834,7 +1834,7 @@ async fn lookup_chat_by_reply(
     Ok(Some((parent_chat.id, parent_chat.blocked)))
 }
 
-#[expect(clippy::too_many_arguments)]
+#[allow(clippy::too_many_arguments)]
 async fn lookup_chat_or_create_adhoc_group(
     context: &Context,
     mime_parser: &MimeMessage,
@@ -1969,7 +1969,7 @@ async fn is_probably_private_reply(
 /// than two members, a new ad hoc group is created.
 ///
 /// On success the function returns the created (chat_id, chat_blocked) tuple.
-#[expect(clippy::too_many_arguments)]
+#[allow(clippy::too_many_arguments)]
 async fn create_group(
     context: &Context,
     mime_parser: &mut MimeMessage,
@@ -2089,6 +2089,7 @@ async fn create_group(
 /// just omitted.
 ///
 /// * `is_partial_download` - whether the message is not fully downloaded.
+#[allow(clippy::too_many_arguments)]
 async fn apply_group_changes(
     context: &Context,
     mime_parser: &mut MimeMessage,
diff --git a/src/smtp.rs b/src/smtp.rs
index 84b0936426..7bc51a2780 100644
--- a/src/smtp.rs
+++ b/src/smtp.rs
@@ -104,7 +104,7 @@ impl Smtp {
     }
 
     /// Connect using the provided login params.
-    #[expect(clippy::too_many_arguments)]
+    #[allow(clippy::too_many_arguments)]
     pub async fn connect(
         &mut self,
         context: &Context,
diff --git a/src/smtp/connect.rs b/src/smtp/connect.rs
index 869405cd30..5652d14272 100644
--- a/src/smtp/connect.rs
+++ b/src/smtp/connect.rs
@@ -45,7 +45,7 @@ async fn new_smtp_transport<S: AsyncBufRead + AsyncWrite + Unpin>(
     Ok(transport)
 }
 
-#[expect(clippy::too_many_arguments)]
+#[allow(clippy::too_many_arguments)]
 pub(crate) async fn connect_and_auth(
     context: &Context,
     proxy_config: &Option<ProxyConfig>,