diff --git a/src/dc_mimeparser.rs b/src/dc_mimeparser.rs
index 13754bc68..3111849e0 100644
--- a/src/dc_mimeparser.rs
+++ b/src/dc_mimeparser.rs
@@ -50,7 +50,7 @@ pub struct dc_mimeparser_t<'a> {
     pub header_root: *mut mailimf_fields,
     pub header_protected: *mut mailimf_fields,
     pub subject: *mut libc::c_char,
-    pub is_send_by_messenger: libc::c_int,
+    pub is_send_by_messenger: bool,
     pub decrypting_failed: libc::c_int,
     pub e2ee_helper: dc_e2ee_helper_t,
     pub is_forwarded: libc::c_int,
@@ -72,7 +72,7 @@ pub unsafe fn dc_mimeparser_new(context: &Context) -> dc_mimeparser_t {
         header_root: std::ptr::null_mut(),
         header_protected: std::ptr::null_mut(),
         subject: std::ptr::null_mut(),
-        is_send_by_messenger: 0,
+        is_send_by_messenger: false,
         decrypting_failed: 0,
         e2ee_helper: Default::default(),
         is_forwarded: 0,
@@ -99,7 +99,7 @@ unsafe fn dc_mimeparser_empty(mimeparser: &mut dc_mimeparser_t) {
         mailimf_fields_free(mimeparser.header_protected);
         mimeparser.header_protected = 0 as *mut mailimf_fields
     }
-    mimeparser.is_send_by_messenger = 0i32;
+    mimeparser.is_send_by_messenger = false;
     mimeparser.is_system_message = 0i32;
     free(mimeparser.subject as *mut libc::c_void);
     mimeparser.subject = 0 as *mut libc::c_char;
@@ -148,7 +148,7 @@ pub unsafe fn dc_mimeparser_parse<'a>(context: &'a Context, body: &[u8]) -> dc_m
             mimeparser.subject = dc_decode_header_words((*(*field).fld_data.fld_subject).sbj_value)
         }
         if !dc_mimeparser_lookup_optional_field(&mut mimeparser, "Chat-Version").is_null() {
-            mimeparser.is_send_by_messenger = 1i32
+            mimeparser.is_send_by_messenger = true
         }
         if !dc_mimeparser_lookup_field(&mut mimeparser, "Autocrypt-Setup-Message").is_null() {
             let mut has_setup_file: libc::c_int = 0i32;
@@ -206,7 +206,7 @@ pub unsafe fn dc_mimeparser_parse<'a>(context: &'a Context, body: &[u8]) -> dc_m
                 }
             }
         }
-        if 0 != mimeparser.is_send_by_messenger
+        if mimeparser.is_send_by_messenger
             && 0 != S_GENERATE_COMPOUND_MSGS
             && mimeparser.parts.len() == 2
         {
@@ -249,7 +249,7 @@ pub unsafe fn dc_mimeparser_parse<'a>(context: &'a Context, body: &[u8]) -> dc_m
                 let p: *mut libc::c_char = strchr(mimeparser.subject, ':' as i32);
                 if p.wrapping_offset_from(mimeparser.subject) == 2
                     || p.wrapping_offset_from(mimeparser.subject) == 3
-                    || 0 != mimeparser.is_send_by_messenger
+                    || mimeparser.is_send_by_messenger
                     || !strstr(
                         mimeparser.subject,
                         b"Chat:\x00" as *const u8 as *const libc::c_char,
@@ -357,7 +357,7 @@ pub unsafe fn dc_mimeparser_parse<'a>(context: &'a Context, body: &[u8]) -> dc_m
     if dc_mimeparser_get_last_nonmeta(&mut mimeparser).is_none() && mimeparser.reports.is_empty() {
         let mut part_5 = dc_mimepart_new();
         part_5.type_0 = 10i32;
-        if !mimeparser.subject.is_null() && 0 == mimeparser.is_send_by_messenger {
+        if !mimeparser.subject.is_null() && !mimeparser.is_send_by_messenger {
             part_5.msg = dc_strdup(mimeparser.subject)
         } else {
             part_5.msg = dc_strdup(b"\x00" as *const u8 as *const libc::c_char)
diff --git a/src/dc_receive_imf.rs b/src/dc_receive_imf.rs
index af42bfab9..095bf1c3d 100644
--- a/src/dc_receive_imf.rs
+++ b/src/dc_receive_imf.rs
@@ -362,7 +362,7 @@ unsafe fn add_parts(
     }
 
     // 1 or 0 for yes/no
-    msgrmsg = mime_parser.is_send_by_messenger;
+    msgrmsg = mime_parser.is_send_by_messenger as _;
     if msgrmsg == 0 && 0 != dc_is_reply_to_messenger_message(context, mime_parser) {
         // 2=no, but is reply to messenger message
         msgrmsg = 2;
@@ -908,11 +908,11 @@ unsafe fn handle_reports(
                 }
             }
 
-            if 0 != mime_parser.is_send_by_messenger || 0 != mdn_consumed {
+            if mime_parser.is_send_by_messenger || 0 != mdn_consumed {
                 let mut param = Params::new();
                 param.set(Param::ServerFolder, server_folder.as_ref());
                 param.set_int(Param::ServerUid, server_uid as i32);
-                if 0 != mime_parser.is_send_by_messenger
+                if mime_parser.is_send_by_messenger
                     && 0 != context
                         .sql
                         .get_config_int(context, "mvbox_move")
@@ -1433,7 +1433,7 @@ unsafe fn create_or_lookup_group(
 
     // check the number of receivers -
     // the only critical situation is if the user hits "Reply" instead of "Reply all" in a non-messenger-client */
-    if to_ids_cnt == 1 && mime_parser.is_send_by_messenger == 0 {
+    if to_ids_cnt == 1 && !mime_parser.is_send_by_messenger {
         let is_contact_cnt = chat::get_chat_contact_cnt(context, chat_id);
         if is_contact_cnt > 3 {
             // to_ids_cnt==1 may be "From: A, To: B, SELF" as SELF is not counted in to_ids_cnt.