diff --git a/acronyms_expander/acronyms_expander.py b/acronyms_expander/acronyms_expander.py
index b216645..74d80a2 100644
--- a/acronyms_expander/acronyms_expander.py
+++ b/acronyms_expander/acronyms_expander.py
@@ -14,6 +14,7 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with Acronyms Expander. If not, see <http://www.gnu.org/licenses/>.
+from __future__ import annotations
 
 import json
 import logging
@@ -21,9 +22,14 @@ from pathlib import Path
 from functools import partial
 
 from gi.repository import GLib
+from gi.repository import GObject
 from gi.repository import Gtk
 
 from gajim.common import configpaths
+from gajim.common import types
+from gajim.common.modules.contacts import GroupchatContact
+
+from gajim.gui.message_input import MessageInputTextView
 
 from gajim.plugins import GajimPlugin
 from gajim.plugins.plugins_i18n import _
@@ -35,21 +41,25 @@ log = logging.getLogger('gajim.p.acronyms')
 
 
 class AcronymsExpanderPlugin(GajimPlugin):
-    def init(self):
+    def init(self) -> None:
         self.description = _('Replaces acronyms (or other strings) '
                              'with given expansions/substitutes.')
         self.config_dialog = partial(ConfigDialog, self)
         self.gui_extension_points = {
-            'chat_control_base': (self._connect, self._disconnect)
+            'message_input': (self._connect, None),
+            'switch_contact': (self._on_switch_contact, None)
         }
         self._invoker = ' '
         self._replace_in_progress = False
-        self._handler_ids = {}
+
+        self._signal_id = None
+        self._text_buffer = None
+        self._contact = None
 
         self.acronyms = self._load_acronyms()
 
     @staticmethod
-    def _load_acronyms():
+    def _load_acronyms() -> dict[str, str]:
         try:
             data_path = Path(configpaths.get('PLUGINS_DATA'))
         except KeyError:
@@ -65,7 +75,7 @@ class AcronymsExpanderPlugin(GajimPlugin):
         return acronyms
 
     @staticmethod
-    def _save_acronyms(acronyms):
+    def _save_acronyms(acronyms: dict[str, str]) -> None:
         try:
             data_path = Path(configpaths.get('PLUGINS_DATA'))
         except KeyError:
@@ -80,11 +90,14 @@ class AcronymsExpanderPlugin(GajimPlugin):
         with filepath.open('w') as file:
             json.dump(acronyms, file)
 
-    def set_acronyms(self, acronyms):
+    def set_acronyms(self, acronyms: dict[str, str]) -> None:
         self.acronyms = acronyms
         self._save_acronyms(acronyms)
 
-    def _on_buffer_changed(self, buffer_, contact, account):
+    def _on_buffer_changed(self,
+                           buffer_: Gtk.TextBuffer
+                           ) -> None:
+
         if self._replace_in_progress:
             return
 
@@ -118,13 +131,14 @@ class AcronymsExpanderPlugin(GajimPlugin):
         # Get last word and cut invoker
         last_word = word_start_iter.get_slice(insert_iter)
 
-        if contact.is_groupchat:
-            if last_word in contact.get_user_nicknames():
+        assert self._contact is not None
+        if isinstance(self._contact, GroupchatContact):
+            if last_word in self._contact.get_user_nicknames():
                 log.info('Groupchat participant has same nick as acronym')
                 return
 
-        if contact.is_pm_contact:
-            if last_word == contact.name:
+        if self._contact.is_pm_contact:
+            if last_word == self._contact.name:
                 log.info('Contact name equals acronym')
                 return
 
@@ -139,23 +153,29 @@ class AcronymsExpanderPlugin(GajimPlugin):
                       insert_iter,
                       substitute)
 
-    def _replace_text(self, buffer_, start, end, substitute):
+    def _replace_text(self,
+                      buffer_: Gtk.TextBuffer,
+                      start: Gtk.TextIter,
+                      end: Gtk.TextIter,
+                      substitute: str
+                      ) -> None:
+
         self._replace_in_progress = True
         buffer_.delete(start, end)
         buffer_.insert(start, substitute)
         self._replace_in_progress = False
 
-    def _connect(self, chat_control):
-        text_buffer = chat_control.msg_textview.get_buffer()
-        handler_id = text_buffer.connect('changed',
-                                         self._on_buffer_changed,
-                                         chat_control.contact,
-                                         chat_control.account)
-        self._handler_ids[id(text_buffer)] = handler_id
+    def _on_switch_contact(self, contact: types.ChatContactT) -> None:
+        self._contact = contact
 
-    def _disconnect(self, chat_control):
-        text_buffer = chat_control.msg_textview.get_buffer()
-        handler_id = self._handler_ids.get(id(text_buffer))
-        if handler_id is not None:
-            text_buffer.disconnect(handler_id)
-            del self._handler_ids[id(text_buffer)]
+    def _connect(self, message_input: MessageInputTextView) -> None:
+        self._text_buffer = message_input.get_buffer()
+        self._signal_id = self._text_buffer.connect(
+            'changed', self._on_buffer_changed)
+
+    def deactivate(self) -> None:
+        assert self._text_buffer is not None
+        assert self._signal_id is not None
+        if GObject.signal_handler_is_connected(
+                self._text_buffer, self._signal_id):
+            self._text_buffer.disconnect(self._signal_id)
diff --git a/acronyms_expander/plugin-manifest.json b/acronyms_expander/plugin-manifest.json
index 32763e9..14c2713 100644
--- a/acronyms_expander/plugin-manifest.json
+++ b/acronyms_expander/plugin-manifest.json
@@ -14,8 +14,8 @@
         "win32"
     ],
     "requirements": [
-        "gajim>=1.4.0"
+        "gajim>=1.5.0"
     ],
     "short_name": "acronyms_expander",
-    "version": "1.4.4"
+    "version": "1.4.5"
 }
\ No newline at end of file