diff --git a/python/plugins/MetaSearch/dialogs/maindialog.py b/python/plugins/MetaSearch/dialogs/maindialog.py
index c6ba0c5bd5e5..832b723d6141 100644
--- a/python/plugins/MetaSearch/dialogs/maindialog.py
+++ b/python/plugins/MetaSearch/dialogs/maindialog.py
@@ -392,7 +392,7 @@ def set_bbox_from_map(self):
 
         if crsid != 4326:  # reproject to EPSG:4326
             src = QgsCoordinateReferenceSystem(crsid)
-            dest = QgsCoordinateReferenceSystem(4326)
+            dest = QgsCoordinateReferenceSystem("EPSG:4326")
             xform = QgsCoordinateTransform(src, dest, QgsProject.instance())
             minxy = xform.transform(QgsPointXY(extent.xMinimum(),
                                                extent.yMinimum()))
@@ -562,7 +562,7 @@ def record_clicked(self):
         if record.bbox is not None:
             points = bbox_to_polygon(record.bbox)
             if points is not None:
-                src = QgsCoordinateReferenceSystem(4326)
+                src = QgsCoordinateReferenceSystem("EPSG:4326")
                 dst = self.map.mapSettings().destinationCrs()
                 geom = QgsGeometry.fromWkt(points)
                 if src.postgisSrid() != dst.postgisSrid():
diff --git a/python/plugins/db_manager/dlg_import_vector.py b/python/plugins/db_manager/dlg_import_vector.py
index d3c3230c9a58..f499f5eb758f 100644
--- a/python/plugins/db_manager/dlg_import_vector.py
+++ b/python/plugins/db_manager/dlg_import_vector.py
@@ -209,7 +209,7 @@ def updateInputLayer(self):
 
         srcCrs = self.inLayer.crs()
         if not srcCrs.isValid():
-            srcCrs = QgsCoordinateReferenceSystem(4326)
+            srcCrs = QgsCoordinateReferenceSystem("EPSG:4326")
         self.widgetSourceSrid.setCrs(srcCrs)
         self.widgetTargetSrid.setCrs(srcCrs)
 
diff --git a/python/plugins/processing/tests/CheckValidityAlgorithm.py b/python/plugins/processing/tests/CheckValidityAlgorithm.py
index 74af9adfec93..f0083a73a6ce 100644
--- a/python/plugins/processing/tests/CheckValidityAlgorithm.py
+++ b/python/plugins/processing/tests/CheckValidityAlgorithm.py
@@ -62,7 +62,7 @@ def _make_layer(self, layer_wkb_name):
         wkb_type = getattr(QgsWkbTypes, layer_wkb_name)
         fields.append(QgsField('int_f', QVariant.Int))
         layer = QgsMemoryProviderUtils.createMemoryLayer(
-            '%s_layer' % layer_wkb_name, fields, wkb_type, QgsCoordinateReferenceSystem(4326))
+            '%s_layer' % layer_wkb_name, fields, wkb_type, QgsCoordinateReferenceSystem("EPSG:4326"))
         self.assertTrue(layer.isValid())
         self.assertEqual(layer.wkbType(), wkb_type)
         return layer