diff --git a/app/.github/workflows/main.yml b/app/.github/workflows/main.yml
index 8465553..d8e144d 100644
--- a/app/.github/workflows/main.yml
+++ b/app/.github/workflows/main.yml
@@ -107,7 +107,7 @@ jobs:
 
       - name: Prepare version file
         run: |
-          scripts/generate-build-info.sh ${{ github.sha }}
+          scripts/generate-build-info.sh ${{ github.sha }} ${{ github.ref_name }}
           cat app/build_info.py
 
       - name: Test with pytest
@@ -164,7 +164,7 @@ jobs:
 
       - name: Prepare version file
         run: |
-          scripts/generate-build-info.sh ${{ github.sha }}
+          scripts/generate-build-info.sh ${{ github.sha }} ${{ github.ref_name }}
           cat app/build_info.py
 
       - name: Build image and publish to Docker Registry
diff --git a/app/app/api/views/setting.py b/app/app/api/views/setting.py
index f58c7fb..bf8c1b6 100644
--- a/app/app/api/views/setting.py
+++ b/app/app/api/views/setting.py
@@ -12,7 +12,7 @@ from app.models import (
     SenderFormatEnum,
     AliasSuffixEnum,
 )
-from app.proton.utils import perform_proton_account_unlink
+from app.proton.proton_unlink import perform_proton_account_unlink
 
 
 def setting_to_dict(user: User):
diff --git a/app/app/api/views/user_info.py b/app/app/api/views/user_info.py
index e52e05a..97371e1 100644
--- a/app/app/api/views/user_info.py
+++ b/app/app/api/views/user_info.py
@@ -12,7 +12,7 @@ from app.dashboard.views.index import get_stats
 from app.db import Session
 from app.image_validation import detect_image_format, ImageFormat
 from app.models import ApiKey, File, PartnerUser, User
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from app.session import logout_session
 from app.utils import random_string
 
diff --git a/app/app/auth/views/proton.py b/app/app/auth/views/proton.py
index 8de7776..52e2fb3 100644
--- a/app/app/auth/views/proton.py
+++ b/app/app/auth/views/proton.py
@@ -23,7 +23,7 @@ from app.proton.proton_callback_handler import (
     ProtonCallbackHandler,
     Action,
 )
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from app.utils import sanitize_next_url, sanitize_scheme
 
 _authorization_base_url = PROTON_BASE_URL + "/oauth/authorize"
diff --git a/app/app/build_info.py b/app/app/build_info.py
index c73f88e..94d612e 100644
--- a/app/app/build_info.py
+++ b/app/app/build_info.py
@@ -1,2 +1,3 @@
 SHA1 = "dev"
 BUILD_TIME = "1652365083"
+VERSION = SHA1
diff --git a/app/app/config.py b/app/app/config.py
index 9ec2cb6..7d6ff97 100644
--- a/app/app/config.py
+++ b/app/app/config.py
@@ -62,6 +62,17 @@ def get_env_dict(env_var: str) -> dict[str, str]:
     return result
 
 
+def get_env_csv(env_var: str, default: Optional[str]) -> list[str]:
+    """
+    Get an env variable and convert it into a list of strings separated by,
+    Syntax is: val1,val2
+    """
+    value = os.getenv(env_var, default)
+    if not value:
+        return []
+    return [field.strip() for field in value.split(",") if field.strip()]
+
+
 config_file = os.environ.get("CONFIG")
 if config_file:
     config_file = get_abs_path(config_file)
@@ -171,6 +182,14 @@ FIRST_ALIAS_DOMAIN = os.environ.get("FIRST_ALIAS_DOMAIN") or EMAIL_DOMAIN
 # e.g. [(10, "mx1.hostname."), (10, "mx2.hostname.")]
 EMAIL_SERVERS_WITH_PRIORITY = sl_getenv("EMAIL_SERVERS_WITH_PRIORITY")
 
+PROTON_MX_SERVERS = get_env_csv(
+    "PROTON_MX_SERVERS", "mail.protonmail.ch., mailsec.protonmail.ch."
+)
+
+PROTON_EMAIL_DOMAINS = get_env_csv(
+    "PROTON_EMAIL_DOMAINS", "proton.me, protonmail.com, protonmail.ch, proton.ch, pm.me"
+)
+
 # disable the alias suffix, i.e. the ".random_word" part
 DISABLE_ALIAS_SUFFIX = "DISABLE_ALIAS_SUFFIX" in os.environ
 
diff --git a/app/app/dashboard/views/account_setting.py b/app/app/dashboard/views/account_setting.py
index efd1649..ee46103 100644
--- a/app/app/dashboard/views/account_setting.py
+++ b/app/app/dashboard/views/account_setting.py
@@ -39,7 +39,7 @@ from app.models import (
     SenderFormatEnum,
     UnsubscribeBehaviourEnum,
 )
-from app.proton.utils import perform_proton_account_unlink
+from app.proton.proton_unlink import perform_proton_account_unlink
 from app.utils import (
     random_string,
     CSRFValidationForm,
diff --git a/app/app/dashboard/views/enter_sudo.py b/app/app/dashboard/views/enter_sudo.py
index 8f6b80a..18115d6 100644
--- a/app/app/dashboard/views/enter_sudo.py
+++ b/app/app/dashboard/views/enter_sudo.py
@@ -11,7 +11,7 @@ from app.dashboard.base import dashboard_bp
 from app.extensions import limiter
 from app.log import LOG
 from app.models import PartnerUser, SocialAuth
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from app.utils import sanitize_next_url
 
 _SUDO_GAP = 120
diff --git a/app/app/dashboard/views/pricing.py b/app/app/dashboard/views/pricing.py
index f9cf4a0..6e36056 100644
--- a/app/app/dashboard/views/pricing.py
+++ b/app/app/dashboard/views/pricing.py
@@ -22,7 +22,7 @@ from app.models import (
     PartnerUser,
     PartnerSubscription,
 )
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 
 
 @dashboard_bp.route("/pricing", methods=["GET", "POST"])
diff --git a/app/app/dashboard/views/setting.py b/app/app/dashboard/views/setting.py
index c912dc4..6fcec6f 100644
--- a/app/app/dashboard/views/setting.py
+++ b/app/app/dashboard/views/setting.py
@@ -41,7 +41,8 @@ from app.models import (
     PartnerSubscription,
     UnsubscribeBehaviourEnum,
 )
-from app.proton.utils import get_proton_partner, can_unlink_proton_account
+from app.proton.proton_partner import get_proton_partner
+from app.proton.proton_unlink import can_unlink_proton_account
 from app.utils import (
     random_string,
     CSRFValidationForm,
diff --git a/app/app/dns_utils.py b/app/app/dns_utils.py
index 02ca784..d2fbd85 100644
--- a/app/app/dns_utils.py
+++ b/app/app/dns_utils.py
@@ -115,9 +115,20 @@ class InMemoryDNSClient(DNSClient):
         return self.txt_records.get(hostname, [])
 
 
-def get_network_dns_client() -> NetworkDNSClient:
+global_dns_client: Optional[DNSClient] = None
+
+
+def get_network_dns_client() -> DNSClient:
+    global global_dns_client
+    if global_dns_client is not None:
+        return global_dns_client
     return NetworkDNSClient(NAMESERVERS)
 
 
+def set_global_dns_client(dns_client: Optional[DNSClient]):
+    global global_dns_client
+    global_dns_client = dns_client
+
+
 def get_mx_domains(hostname: str) -> dict[int, list[str]]:
     return get_network_dns_client().get_mx_domains(hostname)
diff --git a/app/app/events/event_dispatcher.py b/app/app/events/event_dispatcher.py
index 2cf29b7..586e6f7 100644
--- a/app/app/events/event_dispatcher.py
+++ b/app/app/events/event_dispatcher.py
@@ -8,7 +8,7 @@ from app.errors import ProtonPartnerNotSetUp
 from app.events.generated import event_pb2
 from app.log import LOG
 from app.models import User, PartnerUser, SyncEvent
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from typing import Optional
 
 NOTIFICATION_CHANNEL = "simplelogin_sync_events"
diff --git a/app/app/events/generated/event_pb2.py b/app/app/events/generated/event_pb2.py
index f56beb6..babfc8d 100644
--- a/app/app/events/generated/event_pb2.py
+++ b/app/app/events/generated/event_pb2.py
@@ -24,7 +24,7 @@ _sym_db = _symbol_database.Default()
 
 
 
-DESCRIPTOR = _descriptor_pool.Default().AddSerializedFile(b'\n\x0b\x65vent.proto\x12\x12simplelogin_events\":\n\x0fUserPlanChanged\x12\x15\n\rplan_end_time\x18\x01 \x01(\r\x12\x10\n\x08lifetime\x18\x02 \x01(\x08\"\r\n\x0bUserDeleted\"\\\n\x0c\x41liasCreated\x12\n\n\x02id\x18\x01 \x01(\r\x12\r\n\x05\x65mail\x18\x02 \x01(\t\x12\x0c\n\x04note\x18\x03 \x01(\t\x12\x0f\n\x07\x65nabled\x18\x04 \x01(\x08\x12\x12\n\ncreated_at\x18\x05 \x01(\r\"T\n\x12\x41liasStatusChanged\x12\n\n\x02id\x18\x01 \x01(\r\x12\r\n\x05\x65mail\x18\x02 \x01(\t\x12\x0f\n\x07\x65nabled\x18\x03 \x01(\x08\x12\x12\n\ncreated_at\x18\x04 \x01(\r\")\n\x0c\x41liasDeleted\x12\n\n\x02id\x18\x01 \x01(\r\x12\r\n\x05\x65mail\x18\x02 \x01(\t\"D\n\x10\x41liasCreatedList\x12\x30\n\x06\x65vents\x18\x01 \x03(\x0b\x32 .simplelogin_events.AliasCreated\"\x93\x03\n\x0c\x45ventContent\x12?\n\x10user_plan_change\x18\x01 \x01(\x0b\x32#.simplelogin_events.UserPlanChangedH\x00\x12\x37\n\x0cuser_deleted\x18\x02 \x01(\x0b\x32\x1f.simplelogin_events.UserDeletedH\x00\x12\x39\n\ralias_created\x18\x03 \x01(\x0b\x32 .simplelogin_events.AliasCreatedH\x00\x12\x45\n\x13\x61lias_status_change\x18\x04 \x01(\x0b\x32&.simplelogin_events.AliasStatusChangedH\x00\x12\x39\n\ralias_deleted\x18\x05 \x01(\x0b\x32 .simplelogin_events.AliasDeletedH\x00\x12\x41\n\x11\x61lias_create_list\x18\x06 \x01(\x0b\x32$.simplelogin_events.AliasCreatedListH\x00\x42\t\n\x07\x63ontent\"y\n\x05\x45vent\x12\x0f\n\x07user_id\x18\x01 \x01(\r\x12\x18\n\x10\x65xternal_user_id\x18\x02 \x01(\t\x12\x12\n\npartner_id\x18\x03 \x01(\r\x12\x31\n\x07\x63ontent\x18\x04 \x01(\x0b\x32 .simplelogin_events.EventContentb\x06proto3')
+DESCRIPTOR = _descriptor_pool.Default().AddSerializedFile(b'\n\x0b\x65vent.proto\x12\x12simplelogin_events\":\n\x0fUserPlanChanged\x12\x15\n\rplan_end_time\x18\x01 \x01(\r\x12\x10\n\x08lifetime\x18\x02 \x01(\x08\"\r\n\x0bUserDeleted\"\\\n\x0c\x41liasCreated\x12\n\n\x02id\x18\x01 \x01(\r\x12\r\n\x05\x65mail\x18\x02 \x01(\t\x12\x0c\n\x04note\x18\x03 \x01(\t\x12\x0f\n\x07\x65nabled\x18\x04 \x01(\x08\x12\x12\n\ncreated_at\x18\x05 \x01(\r\"T\n\x12\x41liasStatusChanged\x12\n\n\x02id\x18\x01 \x01(\r\x12\r\n\x05\x65mail\x18\x02 \x01(\t\x12\x0f\n\x07\x65nabled\x18\x03 \x01(\x08\x12\x12\n\ncreated_at\x18\x04 \x01(\r\")\n\x0c\x41liasDeleted\x12\n\n\x02id\x18\x01 \x01(\r\x12\r\n\x05\x65mail\x18\x02 \x01(\t\"D\n\x10\x41liasCreatedList\x12\x30\n\x06\x65vents\x18\x01 \x03(\x0b\x32 .simplelogin_events.AliasCreated\"\x0e\n\x0cUserUnlinked\"\xce\x03\n\x0c\x45ventContent\x12?\n\x10user_plan_change\x18\x01 \x01(\x0b\x32#.simplelogin_events.UserPlanChangedH\x00\x12\x37\n\x0cuser_deleted\x18\x02 \x01(\x0b\x32\x1f.simplelogin_events.UserDeletedH\x00\x12\x39\n\ralias_created\x18\x03 \x01(\x0b\x32 .simplelogin_events.AliasCreatedH\x00\x12\x45\n\x13\x61lias_status_change\x18\x04 \x01(\x0b\x32&.simplelogin_events.AliasStatusChangedH\x00\x12\x39\n\ralias_deleted\x18\x05 \x01(\x0b\x32 .simplelogin_events.AliasDeletedH\x00\x12\x41\n\x11\x61lias_create_list\x18\x06 \x01(\x0b\x32$.simplelogin_events.AliasCreatedListH\x00\x12\x39\n\ruser_unlinked\x18\x07 \x01(\x0b\x32 .simplelogin_events.UserUnlinkedH\x00\x42\t\n\x07\x63ontent\"y\n\x05\x45vent\x12\x0f\n\x07user_id\x18\x01 \x01(\r\x12\x18\n\x10\x65xternal_user_id\x18\x02 \x01(\t\x12\x12\n\npartner_id\x18\x03 \x01(\r\x12\x31\n\x07\x63ontent\x18\x04 \x01(\x0b\x32 .simplelogin_events.EventContentb\x06proto3')
 
 _globals = globals()
 _builder.BuildMessageAndEnumDescriptors(DESCRIPTOR, _globals)
@@ -43,8 +43,10 @@ if not _descriptor._USE_C_DESCRIPTORS:
   _globals['_ALIASDELETED']._serialized_end=331
   _globals['_ALIASCREATEDLIST']._serialized_start=333
   _globals['_ALIASCREATEDLIST']._serialized_end=401
-  _globals['_EVENTCONTENT']._serialized_start=404
-  _globals['_EVENTCONTENT']._serialized_end=807
-  _globals['_EVENT']._serialized_start=809
-  _globals['_EVENT']._serialized_end=930
+  _globals['_USERUNLINKED']._serialized_start=403
+  _globals['_USERUNLINKED']._serialized_end=417
+  _globals['_EVENTCONTENT']._serialized_start=420
+  _globals['_EVENTCONTENT']._serialized_end=882
+  _globals['_EVENT']._serialized_start=884
+  _globals['_EVENT']._serialized_end=1005
 # @@protoc_insertion_point(module_scope)
diff --git a/app/app/events/generated/event_pb2.pyi b/app/app/events/generated/event_pb2.pyi
index 58914b1..83369fc 100644
--- a/app/app/events/generated/event_pb2.pyi
+++ b/app/app/events/generated/event_pb2.pyi
@@ -57,21 +57,27 @@ class AliasCreatedList(_message.Message):
     events: _containers.RepeatedCompositeFieldContainer[AliasCreated]
     def __init__(self, events: _Optional[_Iterable[_Union[AliasCreated, _Mapping]]] = ...) -> None: ...
 
+class UserUnlinked(_message.Message):
+    __slots__ = ()
+    def __init__(self) -> None: ...
+
 class EventContent(_message.Message):
-    __slots__ = ("user_plan_change", "user_deleted", "alias_created", "alias_status_change", "alias_deleted", "alias_create_list")
+    __slots__ = ("user_plan_change", "user_deleted", "alias_created", "alias_status_change", "alias_deleted", "alias_create_list", "user_unlinked")
     USER_PLAN_CHANGE_FIELD_NUMBER: _ClassVar[int]
     USER_DELETED_FIELD_NUMBER: _ClassVar[int]
     ALIAS_CREATED_FIELD_NUMBER: _ClassVar[int]
     ALIAS_STATUS_CHANGE_FIELD_NUMBER: _ClassVar[int]
     ALIAS_DELETED_FIELD_NUMBER: _ClassVar[int]
     ALIAS_CREATE_LIST_FIELD_NUMBER: _ClassVar[int]
+    USER_UNLINKED_FIELD_NUMBER: _ClassVar[int]
     user_plan_change: UserPlanChanged
     user_deleted: UserDeleted
     alias_created: AliasCreated
     alias_status_change: AliasStatusChanged
     alias_deleted: AliasDeleted
     alias_create_list: AliasCreatedList
-    def __init__(self, user_plan_change: _Optional[_Union[UserPlanChanged, _Mapping]] = ..., user_deleted: _Optional[_Union[UserDeleted, _Mapping]] = ..., alias_created: _Optional[_Union[AliasCreated, _Mapping]] = ..., alias_status_change: _Optional[_Union[AliasStatusChanged, _Mapping]] = ..., alias_deleted: _Optional[_Union[AliasDeleted, _Mapping]] = ..., alias_create_list: _Optional[_Union[AliasCreatedList, _Mapping]] = ...) -> None: ...
+    user_unlinked: UserUnlinked
+    def __init__(self, user_plan_change: _Optional[_Union[UserPlanChanged, _Mapping]] = ..., user_deleted: _Optional[_Union[UserDeleted, _Mapping]] = ..., alias_created: _Optional[_Union[AliasCreated, _Mapping]] = ..., alias_status_change: _Optional[_Union[AliasStatusChanged, _Mapping]] = ..., alias_deleted: _Optional[_Union[AliasDeleted, _Mapping]] = ..., alias_create_list: _Optional[_Union[AliasCreatedList, _Mapping]] = ..., user_unlinked: _Optional[_Union[UserUnlinked, _Mapping]] = ...) -> None: ...
 
 class Event(_message.Message):
     __slots__ = ("user_id", "external_user_id", "partner_id", "content")
diff --git a/app/app/fake_data.py b/app/app/fake_data.py
index 78c5050..6f43db7 100644
--- a/app/app/fake_data.py
+++ b/app/app/fake_data.py
@@ -37,7 +37,7 @@ from app.models import (
     PartnerSubscription,
 )
 from app.pgp_utils import load_public_key
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 
 
 def fake_data():
diff --git a/app/app/jobs/send_event_job.py b/app/app/jobs/send_event_job.py
index 3f5ca61..32dd7d3 100644
--- a/app/app/jobs/send_event_job.py
+++ b/app/app/jobs/send_event_job.py
@@ -14,7 +14,7 @@ from app.models import (
     Job,
     PartnerUser,
 )
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from events.event_sink import EventSink
 
 
diff --git a/app/app/mailbox_utils.py b/app/app/mailbox_utils.py
index 69599c0..9ed2f02 100644
--- a/app/app/mailbox_utils.py
+++ b/app/app/mailbox_utils.py
@@ -2,7 +2,9 @@ import dataclasses
 import secrets
 from enum import Enum
 from typing import Optional
+
 import arrow
+from sqlalchemy.exc import IntegrityError
 
 from app import config
 from app.config import JOB_DELETE_MAILBOX
@@ -351,6 +353,7 @@ def request_mailbox_email_change(
     check_email_for_mailbox(new_email, user)
     if email_ownership_verified:
         mailbox.email = new_email
+        mailbox.new_email = None
     else:
         mailbox.new_email = new_email
     emit_user_audit_log(
@@ -358,7 +361,12 @@ def request_mailbox_email_change(
         action=UserAuditLogAction.UpdateMailbox,
         message=f"Updated mailbox {mailbox.id} email ({new_email}) pre-verified({email_ownership_verified}",
     )
-    Session.commit()
+    try:
+        Session.commit()
+    except IntegrityError:
+        LOG.i(f"This email {new_email} is already pending for some mailbox")
+        Session.rollback()
+        raise MailboxError("Email already in use")
 
     if email_ownership_verified:
         LOG.i(f"User {user} as created a pre-verified mailbox with {new_email}")
diff --git a/app/app/models.py b/app/app/models.py
index 2f57293..3032ba5 100644
--- a/app/app/models.py
+++ b/app/app/models.py
@@ -2838,24 +2838,20 @@ class Mailbox(Base, ModelMixin):
         return len(alias_ids)
 
     def is_proton(self) -> bool:
-        if (
-            self.email.endswith("@proton.me")
-            or self.email.endswith("@protonmail.com")
-            or self.email.endswith("@protonmail.ch")
-            or self.email.endswith("@proton.ch")
-            or self.email.endswith("@pm.me")
-        ):
-            return True
+        for proton_email_domain in config.PROTON_EMAIL_DOMAINS:
+            if self.email.endswith(f"@{proton_email_domain}"):
+                return True
 
         from app.email_utils import get_email_local_part
 
         mx_domains = get_mx_domains(get_email_local_part(self.email))
+
+        proton_mx_domains = config.PROTON_MX_SERVERS
         # Proton is the first domain
-        if mx_domains and mx_domains[0].domain in (
-            "mail.protonmail.ch.",
-            "mailsec.protonmail.ch.",
-        ):
-            return True
+        for prio in mx_domains:
+            for mx_domain in mx_domains[prio]:
+                if mx_domain in proton_mx_domains:
+                    return True
 
         return False
 
diff --git a/app/app/monitor/views.py b/app/app/monitor/views.py
index a248261..6642846 100644
--- a/app/app/monitor/views.py
+++ b/app/app/monitor/views.py
@@ -1,4 +1,4 @@
-from app.build_info import SHA1
+from app.build_info import SHA1, VERSION
 from app.monitor.base import monitor_bp
 
 
@@ -7,6 +7,11 @@ def git_sha1():
     return SHA1
 
 
+@monitor_bp.route("/version")
+def version():
+    return VERSION
+
+
 @monitor_bp.route("/live")
 def live():
     return "live"
diff --git a/app/app/monitor_utils.py b/app/app/monitor_utils.py
new file mode 100644
index 0000000..4780ee5
--- /dev/null
+++ b/app/app/monitor_utils.py
@@ -0,0 +1,8 @@
+from app.build_info import VERSION
+import newrelic.agent
+
+
+def send_version_event(service: str):
+    newrelic.agent.record_custom_event(
+        "ServiceVersion", {"service": service, "version": VERSION}
+    )
diff --git a/app/app/proton/proton_partner.py b/app/app/proton/proton_partner.py
new file mode 100644
index 0000000..7b02e83
--- /dev/null
+++ b/app/app/proton/proton_partner.py
@@ -0,0 +1,23 @@
+from typing import Optional
+
+from app.db import Session
+from app.errors import ProtonPartnerNotSetUp
+from app.models import Partner
+
+PROTON_PARTNER_NAME = "Proton"
+_PROTON_PARTNER: Optional[Partner] = None
+
+
+def get_proton_partner() -> Partner:
+    global _PROTON_PARTNER
+    if _PROTON_PARTNER is None:
+        partner = Partner.get_by(name=PROTON_PARTNER_NAME)
+        if partner is None:
+            raise ProtonPartnerNotSetUp
+        Session.expunge(partner)
+        _PROTON_PARTNER = partner
+    return _PROTON_PARTNER
+
+
+def is_proton_partner(partner: Partner) -> bool:
+    return partner.name == PROTON_PARTNER_NAME
diff --git a/app/app/proton/utils.py b/app/app/proton/proton_unlink.py
similarity index 64%
rename from app/app/proton/utils.py
rename to app/app/proton/proton_unlink.py
index 0bd4ff3..69f5cb9 100644
--- a/app/app/proton/utils.py
+++ b/app/app/proton/proton_unlink.py
@@ -1,31 +1,13 @@
-from typing import Optional
-
 from newrelic import agent
 
 from app.db import Session
-from app.errors import ProtonPartnerNotSetUp
+from app.events.event_dispatcher import EventDispatcher
+from app.events.generated.event_pb2 import EventContent, UserUnlinked
 from app.log import LOG
-from app.models import Partner, PartnerUser, User
+from app.models import User, PartnerUser
+from app.proton.proton_partner import get_proton_partner
 from app.user_audit_log_utils import emit_user_audit_log, UserAuditLogAction
 
-PROTON_PARTNER_NAME = "Proton"
-_PROTON_PARTNER: Optional[Partner] = None
-
-
-def get_proton_partner() -> Partner:
-    global _PROTON_PARTNER
-    if _PROTON_PARTNER is None:
-        partner = Partner.get_by(name=PROTON_PARTNER_NAME)
-        if partner is None:
-            raise ProtonPartnerNotSetUp
-        Session.expunge(partner)
-        _PROTON_PARTNER = partner
-    return _PROTON_PARTNER
-
-
-def is_proton_partner(partner: Partner) -> bool:
-    return partner.name == PROTON_PARTNER_NAME
-
 
 def can_unlink_proton_account(user: User) -> bool:
     return (user.flags & User.FLAG_CREATED_FROM_PARTNER) == 0
@@ -45,6 +27,9 @@ def perform_proton_account_unlink(current_user: User) -> bool:
             action=UserAuditLogAction.UnlinkAccount,
             message=f"User has unlinked the account (email={partner_user.partner_email} | external_user_id={partner_user.external_user_id})",
         )
+        EventDispatcher.send_event(
+            partner_user.user, EventContent(user_unlinked=UserUnlinked())
+        )
         PartnerUser.delete(partner_user.id)
     Session.commit()
     agent.record_custom_event("AccountUnlinked", {"partner": proton_partner.name})
diff --git a/app/cron.py b/app/cron.py
index 76513f9..e22d46e 100644
--- a/app/cron.py
+++ b/app/cron.py
@@ -59,7 +59,7 @@ from app.models import (
     ApiToCookieToken,
 )
 from app.pgp_utils import load_public_key_and_check, PGPException
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from app.user_audit_log_utils import emit_user_audit_log, UserAuditLogAction
 from app.utils import sanitize_email
 from server import create_light_app
diff --git a/app/email_handler.py b/app/email_handler.py
index 114ab31..f732fb7 100644
--- a/app/email_handler.py
+++ b/app/email_handler.py
@@ -167,6 +167,7 @@ from app.models import (
     VerpType,
     SLDomain,
 )
+from app.monitor_utils import send_version_event
 from app.pgp_utils import (
     PGPException,
     sign_data_with_pgpy,
@@ -2360,6 +2361,7 @@ class MailHandler:
             "Custom/nb_rcpt_tos", len(envelope.rcpt_tos)
         )
 
+        send_version_event("email_handler")
         with create_light_app().app_context():
             return_status = handle(envelope, msg)
             elapsed = time.time() - start
@@ -2395,6 +2397,7 @@ def main(port: int):
 
     controller.start()
     LOG.d("Start mail controller %s %s", controller.hostname, controller.port)
+    send_version_event("email_handler")
 
     if LOAD_PGP_EMAIL_HANDLER:
         LOG.w("LOAD PGP keys")
diff --git a/app/event_listener.py b/app/event_listener.py
index 5c87460..038ef8d 100644
--- a/app/event_listener.py
+++ b/app/event_listener.py
@@ -4,6 +4,7 @@ from sys import argv, exit
 
 from app.config import EVENT_LISTENER_DB_URI
 from app.log import LOG
+from app.monitor_utils import send_version_event
 from events import event_debugger
 from events.runner import Runner
 from events.event_source import DeadLetterEventSource, PostgresEventSource
@@ -30,9 +31,11 @@ def main(mode: Mode, dry_run: bool, max_retries: int):
     if mode == Mode.DEAD_LETTER:
         LOG.i("Using DeadLetterEventSource")
         source = DeadLetterEventSource(max_retries)
+        service_name = "event_listener_dead_letter"
     elif mode == Mode.LISTENER:
         LOG.i("Using PostgresEventSource")
         source = PostgresEventSource(EVENT_LISTENER_DB_URI)
+        service_name = "event_listener"
     else:
         raise ValueError(f"Invalid mode: {mode}")
 
@@ -43,7 +46,8 @@ def main(mode: Mode, dry_run: bool, max_retries: int):
         LOG.i("Starting with HttpEventSink")
         sink = HttpEventSink()
 
-    runner = Runner(source=source, sink=sink)
+    send_version_event(service_name)
+    runner = Runner(source=source, sink=sink, service_name=service_name)
     runner.run()
 
 
diff --git a/app/events/runner.py b/app/events/runner.py
index 0fe7bff..2fa4730 100644
--- a/app/events/runner.py
+++ b/app/events/runner.py
@@ -4,20 +4,24 @@ import newrelic.agent
 from app.log import LOG
 from app.db import Session
 from app.models import SyncEvent
+from app.monitor_utils import send_version_event
 from events.event_sink import EventSink
 from events.event_source import EventSource
 
 
 class Runner:
-    def __init__(self, source: EventSource, sink: EventSink):
+    def __init__(self, source: EventSource, sink: EventSink, service_name: str = ""):
         self.__source = source
         self.__sink = sink
+        self.__service_name = service_name
 
     def run(self):
         self.__source.run(self.__on_event)
 
     @newrelic.agent.background_task()
     def __on_event(self, event: SyncEvent):
+        if self.__service_name:
+            send_version_event(self.__service_name)
         try:
             event_created_at = event.created_at
             start_time = arrow.now()
diff --git a/app/init_app.py b/app/init_app.py
index ced9087..3e3333c 100644
--- a/app/init_app.py
+++ b/app/init_app.py
@@ -6,7 +6,7 @@ from app.db import Session
 from app.log import LOG
 from app.models import Mailbox, Contact, SLDomain, Partner
 from app.pgp_utils import load_public_key
-from app.proton.utils import PROTON_PARTNER_NAME
+from app.proton.proton_partner import PROTON_PARTNER_NAME
 from server import create_light_app
 
 
diff --git a/app/job_runner.py b/app/job_runner.py
index af99fe8..85b32ad 100644
--- a/app/job_runner.py
+++ b/app/job_runner.py
@@ -21,6 +21,7 @@ from app.jobs.export_user_data_job import ExportUserDataJob
 from app.jobs.send_event_job import SendEventToWebhookJob
 from app.log import LOG
 from app.models import User, Job, BatchImport, Mailbox, CustomDomain, JobState
+from app.monitor_utils import send_version_event
 from app.user_audit_log_utils import emit_user_audit_log, UserAuditLogAction
 from server import create_light_app
 
@@ -189,6 +190,7 @@ SimpleLogin team.
 
 
 def process_job(job: Job):
+    send_version_event("job_runner")
     if job.name == config.JOB_ONBOARDING_1:
         user_id = job.payload.get("user_id")
         user = User.get(user_id)
@@ -334,6 +336,7 @@ def get_jobs_to_run() -> List[Job]:
 
 
 if __name__ == "__main__":
+    send_version_event("job_runner")
     while True:
         # wrap in an app context to benefit from app setup like database cleanup, sentry integration, etc
         with create_light_app().app_context():
diff --git a/app/proto/event.proto b/app/proto/event.proto
index 89621f8..1d29ab4 100644
--- a/app/proto/event.proto
+++ b/app/proto/event.proto
@@ -34,6 +34,9 @@ message AliasCreatedList {
   repeated AliasCreated events = 1;
 }
 
+message UserUnlinked {
+}
+
 message EventContent {
   oneof content {
     UserPlanChanged user_plan_change = 1;
@@ -42,6 +45,7 @@ message EventContent {
     AliasStatusChanged alias_status_change = 4;
     AliasDeleted alias_deleted = 5;
     AliasCreatedList alias_create_list = 6;
+    UserUnlinked user_unlinked = 7;
   }
 }
 
diff --git a/app/scripts/generate-build-info.sh b/app/scripts/generate-build-info.sh
index 000b4f4..1149d36 100755
--- a/app/scripts/generate-build-info.sh
+++ b/app/scripts/generate-build-info.sh
@@ -4,12 +4,14 @@ SCRIPT_DIR="$(cd "$(dirname "$0")" || exit 1; pwd -P)"
 REPO_ROOT=$(echo "${SCRIPT_DIR}" | sed 's:scripts::g')
 BUILD_INFO_FILE="${REPO_ROOT}/app/build_info.py"
 
-if [[ -z "$1" ]]; then
-  echo "This script needs to be invoked with the version as an argument"
+if [[ -z "$2" ]]; then
+  echo "Invalid usage. Usage: $0 SHA VERSION"
   exit 1
 fi
 
-VERSION="$1"
-echo "SHA1 = \"${VERSION}\"" > $BUILD_INFO_FILE
+SHA="$1"
+echo "SHA1 = \"${SHA}\"" > $BUILD_INFO_FILE
 BUILD_TIME=$(date +%s)
 echo "BUILD_TIME = \"${BUILD_TIME}\"" >> $BUILD_INFO_FILE
+VERSION="$2"
+echo "VERSION = \"${VERSION}\"" >> $BUILD_INFO_FILE
diff --git a/app/server.py b/app/server.py
index ece49e4..bc54cf7 100644
--- a/app/server.py
+++ b/app/server.py
@@ -99,6 +99,7 @@ from app.models import (
     InvalidMailboxDomain,
 )
 from app.monitor.base import monitor_bp
+from app.monitor_utils import send_version_event
 from app.newsletter_utils import send_newsletter_to_user
 from app.oauth.base import oauth_bp
 from app.onboarding.base import onboarding_bp
@@ -295,6 +296,7 @@ def set_index_page(app):
             newrelic.agent.record_custom_event(
                 "HttpResponseStatus", {"code": res.status_code}
             )
+            send_version_event("app")
         return res
 
 
diff --git a/app/tests/api/test_user_info.py b/app/tests/api/test_user_info.py
index dd539d8..b260df8 100644
--- a/app/tests/api/test_user_info.py
+++ b/app/tests/api/test_user_info.py
@@ -3,7 +3,7 @@ from flask import url_for
 from app import config
 from app.db import Session
 from app.models import User, PartnerUser
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from tests.api.utils import get_new_user_and_api_key
 from tests.utils import login, random_token, random_email
 
diff --git a/app/tests/cron/test_get_alias_for_hibp.py b/app/tests/cron/test_get_alias_for_hibp.py
index 370c6ff..9f645f3 100644
--- a/app/tests/cron/test_get_alias_for_hibp.py
+++ b/app/tests/cron/test_get_alias_for_hibp.py
@@ -14,7 +14,7 @@ from app.models import (
     PartnerSubscription,
     User,
 )
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from tests.utils import create_new_user, random_token
 
 
diff --git a/app/tests/events/event_test_utils.py b/app/tests/events/event_test_utils.py
index d7b6e96..1979ff0 100644
--- a/app/tests/events/event_test_utils.py
+++ b/app/tests/events/event_test_utils.py
@@ -1,7 +1,7 @@
 from app.events.event_dispatcher import Dispatcher
 from app.events.generated import event_pb2
 from app.models import PartnerUser, User
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from tests.utils import create_new_user, random_token
 from typing import Tuple
 
diff --git a/app/tests/jobs/test_send_event_to_webhook.py b/app/tests/jobs/test_send_event_to_webhook.py
index dacc480..245240a 100644
--- a/app/tests/jobs/test_send_event_to_webhook.py
+++ b/app/tests/jobs/test_send_event_to_webhook.py
@@ -4,7 +4,7 @@ from app import config
 from app.events.generated.event_pb2 import EventContent, AliasDeleted
 from app.jobs.send_event_job import SendEventToWebhookJob
 from app.models import PartnerUser
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from events.event_sink import ConsoleEventSink
 from tests.utils import create_new_user, random_token
 
diff --git a/app/tests/models/test_mailbox.py b/app/tests/models/test_mailbox.py
new file mode 100644
index 0000000..68f5d1f
--- /dev/null
+++ b/app/tests/models/test_mailbox.py
@@ -0,0 +1,37 @@
+from app import config
+from app.dns_utils import set_global_dns_client, InMemoryDNSClient
+from app.email_utils import get_email_local_part
+from app.models import Mailbox
+from tests.utils import create_new_user, random_email
+
+dns_client = InMemoryDNSClient()
+
+
+def setup_module():
+    set_global_dns_client(dns_client)
+
+
+def teardown_module():
+    set_global_dns_client(None)
+
+
+def test_is_proton_with_email_domain():
+    user = create_new_user()
+    mailbox = Mailbox.create(
+        user_id=user.id, email=f"test@{config.PROTON_EMAIL_DOMAINS[0]}"
+    )
+    assert mailbox.is_proton()
+    mailbox = Mailbox.create(user_id=user.id, email="a@b.c")
+    assert not mailbox.is_proton()
+
+
+def test_is_proton_with_mx_domain():
+    email = random_email()
+    dns_client.set_mx_records(
+        get_email_local_part(email), {10: config.PROTON_MX_SERVERS}
+    )
+    user = create_new_user()
+    mailbox = Mailbox.create(user_id=user.id, email=email)
+    assert mailbox.is_proton()
+    dns_client.set_mx_records(get_email_local_part(email), {10: ["nowhere.net"]})
+    assert not mailbox.is_proton()
diff --git a/app/tests/models/test_user.py b/app/tests/models/test_user.py
index 211cb3f..11c39eb 100644
--- a/app/tests/models/test_user.py
+++ b/app/tests/models/test_user.py
@@ -2,7 +2,7 @@ import arrow
 from app import config
 from app.db import Session
 from app.models import User, Job, PartnerSubscription, PartnerUser, ManualSubscription
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from tests.utils import random_email, random_token
 
 
diff --git a/app/tests/proton/test_account_linking.py b/app/tests/proton/test_account_linking.py
index d2511c0..8aa9c73 100644
--- a/app/tests/proton/test_account_linking.py
+++ b/app/tests/proton/test_account_linking.py
@@ -7,7 +7,7 @@ from app.account_linking import (
 )
 from app.db import Session
 from app.models import User, PartnerUser, PartnerSubscription
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from app.utils import random_string
 from tests.utils import random_email
 
diff --git a/app/tests/proton/test_proton_callback_handler.py b/app/tests/proton/test_proton_callback_handler.py
index adf8711..00edd4c 100644
--- a/app/tests/proton/test_proton_callback_handler.py
+++ b/app/tests/proton/test_proton_callback_handler.py
@@ -11,7 +11,7 @@ from app.proton.proton_callback_handler import (
     generate_account_not_allowed_to_log_in,
 )
 from app.models import User, PartnerUser, Job, JobState
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from app.utils import random_string
 from typing import Optional
 from tests.utils import random_email
diff --git a/app/tests/test_account_linking.py b/app/tests/test_account_linking.py
index a452423..b38448f 100644
--- a/app/tests/test_account_linking.py
+++ b/app/tests/test_account_linking.py
@@ -19,7 +19,7 @@ from app.account_linking import (
 from app.db import Session
 from app.errors import AccountAlreadyLinkedToAnotherPartnerException
 from app.models import Partner, PartnerUser, User, UserAuditLog
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from app.user_audit_log_utils import UserAuditLogAction
 from app.utils import random_string, canonicalize_email
 from tests.utils import random_email
diff --git a/app/tests/test_alias_suffixes.py b/app/tests/test_alias_suffixes.py
index 870baa1..b1be294 100644
--- a/app/tests/test_alias_suffixes.py
+++ b/app/tests/test_alias_suffixes.py
@@ -3,7 +3,7 @@ import re
 from app.alias_suffix import get_alias_suffixes
 from app.db import Session
 from app.models import SLDomain, PartnerUser, AliasOptions, CustomDomain
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from init_app import add_sl_domains
 from tests.utils import create_new_user, random_token
 
diff --git a/app/tests/test_coupon_utils.py b/app/tests/test_coupon_utils.py
index e947591..743f4ef 100644
--- a/app/tests/test_coupon_utils.py
+++ b/app/tests/test_coupon_utils.py
@@ -18,7 +18,7 @@ from app.models import (
     PartnerSubscription,
     PartnerUser,
 )
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from tests.utils import create_new_user, random_string, random_email
 
 
diff --git a/app/tests/test_custom_domain_validation.py b/app/tests/test_custom_domain_validation.py
index c417fe2..fbeb54d 100644
--- a/app/tests/test_custom_domain_validation.py
+++ b/app/tests/test_custom_domain_validation.py
@@ -6,7 +6,7 @@ from app.custom_domain_validation import CustomDomainValidation
 from app.db import Session
 from app.dns_utils import InMemoryDNSClient
 from app.models import CustomDomain, User
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from app.utils import random_string
 from tests.utils import create_new_user, random_domain
 
diff --git a/app/tests/test_domains.py b/app/tests/test_domains.py
index 5783aa0..58c28e3 100644
--- a/app/tests/test_domains.py
+++ b/app/tests/test_domains.py
@@ -1,6 +1,6 @@
 from app.db import Session
 from app.models import SLDomain, PartnerUser, AliasOptions
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from init_app import add_sl_domains
 from tests.utils import create_new_user, random_token
 
diff --git a/app/tests/test_mailbox_utils.py b/app/tests/test_mailbox_utils.py
index 86d928a..ed33c00 100644
--- a/app/tests/test_mailbox_utils.py
+++ b/app/tests/test_mailbox_utils.py
@@ -25,7 +25,6 @@ from app.user_audit_log_utils import UserAuditLogAction
 from app.utils import random_string, canonicalize_email
 from tests.utils import create_new_user, random_email
 
-
 user: Optional[User] = None
 
 
@@ -598,3 +597,47 @@ def test_change_mailbox_verified_address(flask_client):
     assert changed_mailbox.email == mail2
     assert out.activation is None
     assert 0 == len(mail_sender.get_stored_emails())
+
+
+def test_change_mailbox_email_duplicate(flask_client):
+    user = create_new_user()
+    domain = f"{random_string(10)}.com"
+    mail1 = f"mail_1@{domain}"
+    mbox = Mailbox.create(email=mail1, user_id=user.id, verified=True, flush=True)
+    mail2 = f"mail_2@{domain}"
+    request_mailbox_email_change(user, mbox, mail2, email_ownership_verified=True)
+    with pytest.raises(mailbox_utils.MailboxError):
+        request_mailbox_email_change(user, mbox, mail2, email_ownership_verified=True)
+
+
+def test_change_mailbox_email_duplicate_in_another_mailbox(flask_client):
+    user = create_new_user()
+    domain = f"{random_string(10)}.com"
+    mail1 = f"mail_1@{domain}"
+    mbox1 = Mailbox.create(email=mail1, user_id=user.id, verified=True, flush=True)
+    mail2 = f"mail_2@{domain}"
+    mbox2 = Mailbox.create(email=mail2, user_id=user.id, verified=True, flush=True)
+    mail3 = f"mail_3@{domain}"
+    request_mailbox_email_change(user, mbox1, mail3)
+    with pytest.raises(mailbox_utils.MailboxError):
+        request_mailbox_email_change(user, mbox2, mail3)
+
+
+def test_change_mailbox_verified_email_clears_pending_email(flask_client):
+    user = create_new_user()
+    domain = f"{random_string(10)}.com"
+    mail = f"mail_1@{domain}"
+    mbox1 = Mailbox.create(
+        email=mail,
+        new_email=f"oldpending_{mail}",
+        user_id=user.id,
+        verified=True,
+        flush=True,
+    )
+    new_email = f"new_{mail}"
+    out = request_mailbox_email_change(
+        user, mbox1, new_email, email_ownership_verified=True
+    )
+    assert out.activation is None
+    assert out.mailbox.email == new_email
+    assert out.mailbox.new_email is None
diff --git a/app/tests/utils.py b/app/tests/utils.py
index 179cbb2..b7798d0 100644
--- a/app/tests/utils.py
+++ b/app/tests/utils.py
@@ -10,7 +10,7 @@ import jinja2
 from flask import url_for
 
 from app.models import User, PartnerUser
-from app.proton.utils import get_proton_partner
+from app.proton.proton_partner import get_proton_partner
 from app.utils import random_string