diff --git a/src/chat.rs b/src/chat.rs
index 6fd77cd63..cc0f9a044 100644
--- a/src/chat.rs
+++ b/src/chat.rs
@@ -879,7 +879,7 @@ pub fn send_text_msg(
 ) -> Result<MsgId, Error> {
     ensure!(
         chat_id > DC_CHAT_ID_LAST_SPECIAL,
-        "bad chat_id = {} <= 9",
+        "bad chat_id = {} <= DC_CHAT_ID_LAST_SPECIAL",
         chat_id
     );
 
@@ -1254,7 +1254,7 @@ pub fn get_next_media(
 pub fn archive(context: &Context, chat_id: u32, archive: bool) -> Result<(), Error> {
     ensure!(
         chat_id > DC_CHAT_ID_LAST_SPECIAL,
-        "bad chat_id = {} <= 9",
+        "bad chat_id = {} <= DC_CHAT_ID_LAST_SPECIAL",
         chat_id
     );
 
@@ -1289,7 +1289,7 @@ pub fn archive(context: &Context, chat_id: u32, archive: bool) -> Result<(), Err
 pub fn delete(context: &Context, chat_id: u32) -> Result<(), Error> {
     ensure!(
         chat_id > DC_CHAT_ID_LAST_SPECIAL,
-        "bad chat_id = {} <= 9",
+        "bad chat_id = {} <= DC_CHAT_ID_LAST_SPECIAL",
         chat_id
     );
     /* Up to 2017-11-02 deleting a group also implied leaving it, see above why we have changed this. */
@@ -1578,7 +1578,7 @@ pub fn remove_contact_from_chat(
 ) -> Result<(), Error> {
     ensure!(
         chat_id > DC_CHAT_ID_LAST_SPECIAL,
-        "bad chat_id = {} <= 9",
+        "bad chat_id = {} <= DC_CHAT_ID_LAST_SPECIAL",
         chat_id
     );
     ensure!(
diff --git a/src/contact.rs b/src/contact.rs
index dc1de9169..9c18ec8fb 100644
--- a/src/contact.rs
+++ b/src/contact.rs
@@ -876,7 +876,7 @@ impl Contact {
     }
 
     pub fn real_exists_by_id(context: &Context, contact_id: u32) -> bool {
-        if !context.sql.is_open() || contact_id <= 9 {
+        if !context.sql.is_open() || contact_id <= DC_CONTACT_ID_LAST_SPECIAL {
             return false;
         }
 
@@ -923,7 +923,7 @@ pub fn addr_normalize(addr: &str) -> &str {
 }
 
 fn set_block_contact(context: &Context, contact_id: u32, new_blocking: bool) {
-    if contact_id <= 9 {
+    if contact_id <= DC_CONTACT_ID_LAST_SPECIAL {
         return;
     }
 
diff --git a/src/message.rs b/src/message.rs
index bf4cdfecd..aa66591cd 100644
--- a/src/message.rs
+++ b/src/message.rs
@@ -1104,7 +1104,7 @@ pub fn mdn_from_ext(
     rfc724_mid: &str,
     timestamp_sent: i64,
 ) -> Option<(u32, MsgId)> {
-    if from_id <= 9 || rfc724_mid.is_empty() {
+    if from_id <= DC_MSG_ID_LAST_SPECIAL || rfc724_mid.is_empty() {
         return None;
     }