diff --git a/deltachat-ffi/deltachat.h b/deltachat-ffi/deltachat.h
index e4b7df644..dee7ded8a 100644
--- a/deltachat-ffi/deltachat.h
+++ b/deltachat-ffi/deltachat.h
@@ -3956,28 +3956,6 @@ int             dc_chat_is_protected         (const dc_chat_t* chat);
 int             dc_chat_is_encrypted         (const dc_chat_t *chat);
 
 
-/**
- * Checks if the chat was protected, and then an incoming message broke this protection.
- *
- * This function is only useful if the UI enabled the `verified_one_on_one_chats` feature flag,
- * otherwise it will return false for all chats.
- *
- * 1:1 chats are automatically set as protected when a contact is verified.
- * When a message comes in that is not encrypted / signed correctly,
- * the chat is automatically set as unprotected again.
- * dc_chat_is_protection_broken() will return true until dc_accept_chat() is called.
- *
- * The UI should let the user confirm that this is OK with a message like
- * `Bob sent a message from another device. Tap to learn more` and then call dc_accept_chat().
- *
- * @deprecated 2025-07 chats protection cannot break any longer
- * @memberof dc_chat_t
- * @param chat The chat object.
- * @return 1=chat protection broken, 0=otherwise.
- */
-int             dc_chat_is_protection_broken (const dc_chat_t* chat);
-
-
 /**
  * Check if locations are sent to the chat
  * at the time the object was created using dc_get_chat().
diff --git a/deltachat-ffi/src/lib.rs b/deltachat-ffi/src/lib.rs
index ff323b63c..ddae6de52 100644
--- a/deltachat-ffi/src/lib.rs
+++ b/deltachat-ffi/src/lib.rs
@@ -3247,16 +3247,6 @@ pub unsafe extern "C" fn dc_chat_is_encrypted(chat: *mut dc_chat_t) -> libc::c_i
         .unwrap_or_log_default(&ffi_chat.context, "Failed dc_chat_is_encrypted") as libc::c_int
 }
 
-#[no_mangle]
-pub unsafe extern "C" fn dc_chat_is_protection_broken(chat: *mut dc_chat_t) -> libc::c_int {
-    if chat.is_null() {
-        eprintln!("ignoring careless call to dc_chat_is_protection_broken()");
-        return 0;
-    }
-    let ffi_chat = &*chat;
-    ffi_chat.chat.is_protection_broken() as libc::c_int
-}
-
 #[no_mangle]
 pub unsafe extern "C" fn dc_chat_is_sending_locations(chat: *mut dc_chat_t) -> libc::c_int {
     if chat.is_null() {
diff --git a/deltachat-jsonrpc/src/api/types/chat.rs b/deltachat-jsonrpc/src/api/types/chat.rs
index 96388c27b..86f78abee 100644
--- a/deltachat-jsonrpc/src/api/types/chat.rs
+++ b/deltachat-jsonrpc/src/api/types/chat.rs
@@ -71,8 +71,6 @@ pub struct FullChat {
     fresh_message_counter: usize,
     // is_group - please check over chat.type in frontend instead
     is_contact_request: bool,
-    /// Deprecated 2025-07. Chats protection cannot break any longer.
-    is_protection_broken: bool,
 
     is_device_chat: bool,
     self_in_group: bool,
@@ -147,7 +145,6 @@ impl FullChat {
             color,
             fresh_message_counter,
             is_contact_request: chat.is_contact_request(),
-            is_protection_broken: chat.is_protection_broken(),
             is_device_chat: chat.is_device_talk(),
             self_in_group: contact_ids.contains(&ContactId::SELF),
             is_muted: chat.is_muted(),
@@ -218,8 +215,6 @@ pub struct BasicChat {
     is_self_talk: bool,
     color: String,
     is_contact_request: bool,
-    /// Deprecated 2025-07. Chats protection cannot break any longer.
-    is_protection_broken: bool,
 
     is_device_chat: bool,
     is_muted: bool,
@@ -249,7 +244,6 @@ impl BasicChat {
             is_self_talk: chat.is_self_talk(),
             color,
             is_contact_request: chat.is_contact_request(),
-            is_protection_broken: chat.is_protection_broken(),
             is_device_chat: chat.is_device_talk(),
             is_muted: chat.is_muted(),
         })
diff --git a/src/chat.rs b/src/chat.rs
index 3ba491ceb..f0ebdb0c6 100644
--- a/src/chat.rs
+++ b/src/chat.rs
@@ -1920,11 +1920,6 @@ impl Chat {
         Ok(is_encrypted)
     }
 
-    /// Deprecated 2025-07. Returns false.
-    pub fn is_protection_broken(&self) -> bool {
-        false
-    }
-
     /// Returns true if location streaming is enabled in the chat.
     pub fn is_sending_locations(&self) -> bool {
         self.is_sending_locations
diff --git a/src/config.rs b/src/config.rs
index 7bfebd868..b16382cd7 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -422,7 +422,7 @@ pub enum Config {
     /// Regardless of this setting, `chat.is_protected()` returns true while the key is verified,
     /// and when the key changes, an info message is posted into the chat.
     /// 0=Nothing else happens when the key changes.
-    /// 1=After the key changed, `can_send()` returns false and `is_protection_broken()` returns true
+    /// 1=After the key changed, `can_send()` returns false
     /// until `chat_id.accept()` is called.
     #[strum(props(default = "0"))]
     VerifiedOneOnOneChats,
diff --git a/src/tests/verified_chats.rs b/src/tests/verified_chats.rs
index fbee49fc2..2a85dbc02 100644
--- a/src/tests/verified_chats.rs
+++ b/src/tests/verified_chats.rs
@@ -881,7 +881,6 @@ async fn assert_verified(this: &TestContext, other: &TestContext, protected: Pro
         chat.is_protected(),
         protected == ProtectionStatus::Protected
     );
-    assert_eq!(chat.is_protection_broken(), false);
 }
 
 async fn enable_verified_oneonone_chats(test_contexts: &[&TestContext]) {