diff --git a/lib/charms/smtp_integrator/v0/smtp.py b/lib/charms/smtp_integrator/v0/smtp.py
index 454e0987..a13ab9fa 100644
--- a/lib/charms/smtp_integrator/v0/smtp.py
+++ b/lib/charms/smtp_integrator/v0/smtp.py
@@ -58,12 +58,12 @@ def __init__(self, *args):
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
-LIBPATCH = 1
+LIBPATCH = 2
 
 # pylint: disable=wrong-import-position
 import logging
 from enum import Enum
-from typing import Optional
+from typing import Dict, List, Optional
 
 import ops
 from pydantic import BaseModel, Field, ValidationError
@@ -125,7 +125,7 @@ class SmtpRelationData(BaseModel):
     transport_security: TransportSecurity
     domain: Optional[str]
 
-    def to_relation_data(self) -> dict[str, str]:
+    def to_relation_data(self) -> Dict[str, str]:
         """Convert an instance of SmtpRelationData to the relation representation.
 
         Returns:
@@ -306,7 +306,7 @@ def __init__(self, charm: ops.CharmBase, relation_name: str = DEFAULT_RELATION_N
         self.relation_name = relation_name
 
     @property
-    def relations(self) -> list[ops.Relation]:
+    def relations(self) -> List[ops.Relation]:
         """The list of Relation instances associated with this relation_name.
 
         Returns: