diff --git a/src/matrix-event-receipt.vala b/src/matrix-event-receipt.vala
index 89a4c51..3ec56e4 100644
--- a/src/matrix-event-receipt.vala
+++ b/src/matrix-event-receipt.vala
@@ -30,7 +30,7 @@ public class Matrix.Event.Receipt : Matrix.Event.Base {
         string user;
     }
 
-    private HashTable<ReceiptData?, ulong?> _receipt_data = null;
+    private Gee.HashMap<ReceiptData?, ulong?> _receipt_data = null;
 
     private static bool
     _rd_equal(ReceiptData k1, ReceiptData k2)
@@ -43,8 +43,7 @@ public class Matrix.Event.Receipt : Matrix.Event.Base {
     private void
     _init_receipt_data()
     {
-        _receipt_data = new HashTable<ReceiptData?, ulong?>(
-                direct_hash, (EqualFunc)_rd_equal);
+        _receipt_data = new Gee.HashMap<ReceiptData?, ulong?>(null, (Gee.EqualDataFunc)_rd_equal);
     }
 
     protected override void
@@ -76,9 +75,8 @@ public class Matrix.Event.Receipt : Matrix.Event.Base {
                                 user = r_user_id
                             };
 
-                            _receipt_data.replace(
-                                    rd_key,
-                                    (ulong)r_content.get_object().get_member("ts").get_int());
+                            _receipt_data[rd_key] =
+                                (ulong)r_content.get_object().get_member("ts").get_int();
                         });
                 } else {
                     warning("content.$event-id.m.read is missing from a m.presence event");
@@ -103,57 +101,57 @@ public class Matrix.Event.Receipt : Matrix.Event.Base {
         var content_root = root.get_member("content").get_object();
         int i = 0;
 
-        _receipt_data.foreach((key, value) => {
-                Json.Object event_object;
-                Json.Object type_object;
-                Json.Object user_object;
+        foreach (var entry in _receipt_data.entries) {
+            Json.Object event_object;
+            Json.Object type_object;
+            Json.Object user_object;
 
-                if (key.event_id == null) {
-                    throw new Matrix.Error.INCOMPLETE(
-                            "Won't generate a m.receipt event with an empty event ID");
-                }
+            if (entry.key.event_id == null) {
+                throw new Matrix.Error.INCOMPLETE(
+                        "Won't generate a m.receipt event with an empty event ID");
+            }
 
-                if (key.typ == null) {
-                    throw new Matrix.Error.INCOMPLETE(
-                            "Won't generate a m.receipt event with an empty receipt type");
-                }
+            if (entry.key.typ == null) {
+                throw new Matrix.Error.INCOMPLETE(
+                        "Won't generate a m.receipt event with an empty receipt type");
+            }
 
-                if (key.user == null) {
-                    throw new Matrix.Error.INCOMPLETE(
-                            "Won't generate a m.receipt event with an empty user ID");
-                }
+            if (entry.key.user == null) {
+                throw new Matrix.Error.INCOMPLETE(
+                        "Won't generate a m.receipt event with an empty user ID");
+            }
 
-                i++;
+            i++;
 
-                if ((node = content_root.get_member(key.event_id)) == null) {
-                    event_object = new Json.Object();
-                    node = new Json.Node(Json.NodeType.OBJECT);
-                    node.set_object(event_object);
-                    content_root.set_member(key.event_id, node);
-                } else {
-                    event_object = node.get_object();
-                }
+            if ((node = content_root.get_member(entry.key.event_id)) == null) {
+                event_object = new Json.Object();
+                node = new Json.Node(Json.NodeType.OBJECT);
+                node.set_object(event_object);
+                content_root.set_member(entry.key.event_id, node);
+            } else {
+                event_object = node.get_object();
+            }
 
-                if ((node = event_object.get_member(key.typ)) == null) {
-                    type_object = new Json.Object();
-                    node = new Json.Node(Json.NodeType.OBJECT);
-                    node.set_object(type_object);
-                    event_object.set_member(key.typ, node);
-                } else {
-                    type_object = node.get_object();
-                }
+            if ((node = event_object.get_member(entry.key.typ)) == null) {
+                type_object = new Json.Object();
+                node = new Json.Node(Json.NodeType.OBJECT);
+                node.set_object(type_object);
+                event_object.set_member(entry.key.typ, node);
+            } else {
+                type_object = node.get_object();
+            }
 
-                if ((node = type_object.get_member(key.user)) == null) {
-                    user_object = new Json.Object();
-                    node = new Json.Node(Json.NodeType.OBJECT);
-                    node.set_object(user_object);
-                    type_object.set_member(key.user, node);
-                } else {
-                    user_object = node.get_object();
-                }
+            if ((node = type_object.get_member(entry.key.user)) == null) {
+                user_object = new Json.Object();
+                node = new Json.Node(Json.NodeType.OBJECT);
+                node.set_object(user_object);
+                type_object.set_member(entry.key.user, node);
+            } else {
+                user_object = node.get_object();
+            }
 
-                user_object.set_int_member("ts", value);
-            });
+            user_object.set_int_member("ts", entry.value);
+        }
 
         if (i == 0) {
             throw new Matrix.Error.INCOMPLETE(