diff --git a/CHANGELOG.md b/CHANGELOG.md
index 07cdfa9e..259981f8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+## v1.3.5 (2023-07-05)
+
+### Fixed
+
+- Fix for phone provider initialization which can lead to an HTTP 500 on startup ([#2434](https://github.com/grafana/oncall/pull/2434))
+
 ## v1.3.4 (2023-07-05)
 
 ### Added
diff --git a/engine/settings/base.py b/engine/settings/base.py
index b4bbe6e5..aaf1c256 100644
--- a/engine/settings/base.py
+++ b/engine/settings/base.py
@@ -724,8 +724,11 @@ PYROSCOPE_AUTH_TOKEN = os.getenv("PYROSCOPE_AUTH_TOKEN", "")
 PHONE_PROVIDERS = {
     "twilio": "apps.twilioapp.phone_provider.TwilioPhoneProvider",
     # "simple": "apps.phone_notifications.simple_phone_provider.SimplePhoneProvider",
-    "zvonok": "apps.zvonok.phone_provider.ZvonokPhoneProvider",
 }
+
+if IS_OPEN_SOURCE:
+    PHONE_PROVIDERS["zvonok"] = "apps.zvonok.phone_provider.ZvonokPhoneProvider"
+
 PHONE_PROVIDER = os.environ.get("PHONE_PROVIDER", default="twilio")
 
 ZVONOK_API_KEY = os.getenv("ZVONOK_API_KEY", None)