diff --git a/mmime/src/display.rs b/mmime/src/display.rs
index 03c8b075a..4282a58bd 100644
--- a/mmime/src/display.rs
+++ b/mmime/src/display.rs
@@ -221,13 +221,10 @@ unsafe fn display_orig_date(mut orig_date: *mut mailimf_orig_date) {
     display_date_time((*orig_date).dt_date_time);
 }
 unsafe fn display_mailbox(mut mb: *mut mailimf_mailbox) {
-    if !(*mb).mb_display_name.is_null() {
-        print!(
-            "{}",
-            CStr::from_ptr((*mb).mb_display_name).to_str().unwrap()
-        );
+    if !(*mb).display_name.is_null() {
+        print!("{}", CStr::from_ptr((*mb).display_name).to_str().unwrap());
     }
-    print!("<{}>", CStr::from_ptr((*mb).mb_addr_spec).to_str().unwrap());
+    print!("<{}>", CStr::from_ptr((*mb).addr_spec).to_str().unwrap());
 }
 unsafe fn display_mailbox_list(mut mb_list: *mut mailimf_mailbox_list) {
     for (i, mb) in (*mb_list).0.iter().enumerate() {
diff --git a/mmime/src/mailimf/types.rs b/mmime/src/mailimf/types.rs
index 0601a6128..64b996dcf 100644
--- a/mmime/src/mailimf/types.rs
+++ b/mmime/src/mailimf/types.rs
@@ -75,22 +75,26 @@ impl Drop for mailimf_mailbox_list {
     }
 }
 
-/*
-  mailimf_mailbox is a mailbox
-
-  - display_name is the name that will be displayed for this mailbox,
-    for example 'name' in '"name" <mailbox@domain>,
-    should be allocated with malloc()
-
-  - addr_spec is the mailbox, for example 'mailbox@domain'
-    in '"name" <mailbox@domain>, should be allocated with malloc()
-*/
-#[derive(Copy, Clone)]
-#[repr(C)]
+/// A single mailbox.
+#[derive(Clone)]
 pub struct mailimf_mailbox {
-    pub mb_display_name: *mut libc::c_char,
-    pub mb_addr_spec: *mut libc::c_char,
+    /// The name that will be displayed for this mailbox,
+    /// for example 'name' in '"name" <mailbox@domain>.
+    pub display_name: *mut libc::c_char,
+    /// addr_spec is the mailbox, for example 'mailbox@domain'
+    /// in '"name" <mailbox@domain>.
+    pub addr_spec: *mut libc::c_char,
 }
+
+impl Drop for mailimf_mailbox {
+    fn drop(&mut self) {
+        if !self.display_name.is_null() {
+            unsafe { mailimf_display_name_free(self.display_name) };
+        }
+        unsafe { mailimf_addr_spec_free(self.addr_spec) };
+    }
+}
+
 /*
   mailimf_address_list is a list of addresses
 
@@ -518,31 +522,28 @@ pub unsafe fn mailimf_mailbox_list_free(mb_list: *mut mailimf_mailbox_list) {
     let _ = Box::from_raw(mb_list);
 }
 
-#[no_mangle]
-pub unsafe fn mailimf_mailbox_free(mut mailbox: *mut mailimf_mailbox) {
-    if !(*mailbox).mb_display_name.is_null() {
-        mailimf_display_name_free((*mailbox).mb_display_name);
+pub unsafe fn mailimf_mailbox_free(mailbox: *mut mailimf_mailbox) {
+    if mailbox.is_null() {
+        return;
     }
-    mailimf_addr_spec_free((*mailbox).mb_addr_spec);
-    free(mailbox as *mut libc::c_void);
+    let _ = Box::from_raw(mailbox);
 }
+
 #[no_mangle]
 pub unsafe fn mailimf_addr_spec_free(mut addr_spec: *mut libc::c_char) {
     free(addr_spec as *mut libc::c_void);
 }
-#[no_mangle]
-pub unsafe fn mailimf_mailbox_new(
-    mut mb_display_name: *mut libc::c_char,
-    mut mb_addr_spec: *mut libc::c_char,
+
+pub fn mailimf_mailbox_new(
+    display_name: *mut libc::c_char,
+    addr_spec: *mut libc::c_char,
 ) -> *mut mailimf_mailbox {
-    let mut mb: *mut mailimf_mailbox = 0 as *mut mailimf_mailbox;
-    mb = malloc(::std::mem::size_of::<mailimf_mailbox>() as libc::size_t) as *mut mailimf_mailbox;
-    if mb.is_null() {
-        return 0 as *mut mailimf_mailbox;
-    }
-    (*mb).mb_display_name = mb_display_name;
-    (*mb).mb_addr_spec = mb_addr_spec;
-    return mb;
+    let mb = mailimf_mailbox {
+        display_name,
+        addr_spec,
+    };
+
+    Box::into_raw(Box::new(mb))
 }
 
 pub fn mailimf_group_new(
diff --git a/mmime/src/mailimf/write_generic.rs b/mmime/src/mailimf/write_generic.rs
index a623b23f3..016686498 100644
--- a/mmime/src/mailimf/write_generic.rs
+++ b/mmime/src/mailimf/write_generic.rs
@@ -1084,21 +1084,21 @@ unsafe fn mailimf_mailbox_write_driver(
 ) -> libc::c_int {
     let mut r: libc::c_int = 0;
     let mut do_fold: libc::c_int = 0;
-    if !(*mb).mb_display_name.is_null() {
-        if 0 != is_atext((*mb).mb_display_name) {
+    if !(*mb).display_name.is_null() {
+        if 0 != is_atext((*mb).display_name) {
             r = mailimf_header_string_write_driver(
                 do_write,
                 data,
                 col,
-                (*mb).mb_display_name,
-                strlen((*mb).mb_display_name),
+                (*mb).display_name,
+                strlen((*mb).display_name),
             );
             if r != MAILIMF_NO_ERROR as libc::c_int {
                 return r;
             }
         } else {
-            if !(*mb).mb_display_name.is_null() {
-                if (*col as libc::size_t).wrapping_add(strlen((*mb).mb_display_name))
+            if !(*mb).display_name.is_null() {
+                if (*col as libc::size_t).wrapping_add(strlen((*mb).display_name))
                     >= 72i32 as libc::size_t
                 {
                     r = mailimf_string_write_driver(
@@ -1113,15 +1113,15 @@ unsafe fn mailimf_mailbox_write_driver(
                     }
                 }
             }
-            if strlen((*mb).mb_display_name) > (998i32 / 2i32) as libc::size_t {
+            if strlen((*mb).display_name) > (998i32 / 2i32) as libc::size_t {
                 return MAILIMF_ERROR_INVAL as libc::c_int;
             }
             r = mailimf_quoted_string_write_driver(
                 do_write,
                 data,
                 col,
-                (*mb).mb_display_name,
-                strlen((*mb).mb_display_name),
+                (*mb).display_name,
+                strlen((*mb).display_name),
             );
             if r != MAILIMF_NO_ERROR as libc::c_int {
                 return r;
@@ -1130,7 +1130,7 @@ unsafe fn mailimf_mailbox_write_driver(
         do_fold = 0i32;
         if *col > 1i32 {
             if (*col as libc::size_t)
-                .wrapping_add(strlen((*mb).mb_addr_spec))
+                .wrapping_add(strlen((*mb).addr_spec))
                 .wrapping_add(3i32 as libc::size_t)
                 >= 72i32 as libc::size_t
             {
@@ -1171,8 +1171,8 @@ unsafe fn mailimf_mailbox_write_driver(
             do_write,
             data,
             col,
-            (*mb).mb_addr_spec,
-            strlen((*mb).mb_addr_spec),
+            (*mb).addr_spec,
+            strlen((*mb).addr_spec),
         );
         if r != MAILIMF_NO_ERROR as libc::c_int {
             return r;
@@ -1188,8 +1188,7 @@ unsafe fn mailimf_mailbox_write_driver(
             return r;
         }
     } else {
-        if (*col as libc::size_t).wrapping_add(strlen((*mb).mb_addr_spec)) >= 72i32 as libc::size_t
-        {
+        if (*col as libc::size_t).wrapping_add(strlen((*mb).addr_spec)) >= 72i32 as libc::size_t {
             r = mailimf_string_write_driver(
                 do_write,
                 data,
@@ -1205,8 +1204,8 @@ unsafe fn mailimf_mailbox_write_driver(
             do_write,
             data,
             col,
-            (*mb).mb_addr_spec,
-            strlen((*mb).mb_addr_spec),
+            (*mb).addr_spec,
+            strlen((*mb).addr_spec),
         );
         if r != MAILIMF_NO_ERROR as libc::c_int {
             return r;
diff --git a/src/dc_mimeparser.rs b/src/dc_mimeparser.rs
index d65f21330..6585516b3 100644
--- a/src/dc_mimeparser.rs
+++ b/src/dc_mimeparser.rs
@@ -847,7 +847,7 @@ impl<'a> MimeParser<'a> {
                 .unwrap_or_else(|| ptr::null_mut());
 
             if !mb.is_null() {
-                let from_addr_norm = addr_normalize(as_str((*mb).mb_addr_spec));
+                let from_addr_norm = addr_normalize(as_str((*mb).addr_spec));
                 let recipients = mailimf_get_recipients(self.header_root);
                 if recipients.len() == 1 {
                     if recipients.contains(from_addr_norm) {
@@ -916,8 +916,8 @@ pub fn mailimf_find_first_addr(mb_list: *const mailimf_mailbox_list) -> Option<S
 
     for mb in unsafe { &(*mb_list).0 } {
         let mb = *mb;
-        if !mb.is_null() && !unsafe { (*mb).mb_addr_spec.is_null() } {
-            let addr = unsafe { as_str((*mb).mb_addr_spec) };
+        if !mb.is_null() && !unsafe { (*mb).addr_spec.is_null() } {
+            let addr = unsafe { as_str((*mb).addr_spec) };
             return Some(addr_normalize(addr).to_string());
         }
     }
@@ -1272,7 +1272,7 @@ pub fn mailimf_get_recipients(imffields: *mut mailimf_fields) -> HashSet<String>
 
 fn mailimf_get_recipients_add_addr(recipients: &mut HashSet<String>, mb: *mut mailimf_mailbox) {
     if !mb.is_null() {
-        let addr_norm = addr_normalize(as_str(unsafe { (*mb).mb_addr_spec }));
+        let addr_norm = addr_normalize(as_str(unsafe { (*mb).addr_spec }));
         recipients.insert(addr_norm.into());
     }
 }
diff --git a/src/dc_receive_imf.rs b/src/dc_receive_imf.rs
index c1e6ed3b2..dca216573 100644
--- a/src/dc_receive_imf.rs
+++ b/src/dc_receive_imf.rs
@@ -1868,8 +1868,8 @@ unsafe fn dc_add_or_lookup_contacts_by_address_list(
                 if !mb.is_null() {
                     add_or_lookup_contact_by_addr(
                         context,
-                        (*mb).mb_display_name,
-                        (*mb).mb_addr_spec,
+                        (*mb).display_name,
+                        (*mb).addr_spec,
                         origin,
                         ids,
                         check_self,
@@ -1906,8 +1906,8 @@ unsafe fn dc_add_or_lookup_contacts_by_mailbox_list(
         if !mb.is_null() {
             add_or_lookup_contact_by_addr(
                 context,
-                (*mb).mb_display_name,
-                (*mb).mb_addr_spec,
+                (*mb).display_name,
+                (*mb).addr_spec,
                 origin,
                 ids,
                 check_self,