Attached is the notifications_backup.mk that was auto-created during the upgrade. We were running 2.3.0p23, but I upgraded the site to 2.3.0p29 just prior to bumping up to 2.4.0p1.
# Written by Checkmk store
notification_rules += [{'description': 'Downtime Alerts', 'comment': '', 'docu_url': '', 'disabled': False, 'allow_disable': True, 'match_timeperiod': 'WorkingHours', 'match_host_event': ['s'], 'contact_object': False, 'contact_all': False, 'contact_all_with_email': False, 'contact_groups': ['all'], 'notify_plugin': ('asciimail', {'common_body': 'Host: $HOSTNAME$\nAddress: $HOSTADDRESS$\n', 'host_body': 'Event: $EVENT_TXT$\n$LONGHOSTOUTPUT$\n'}), 'bulk': ('always', {'interval': 120, 'count': 1000, 'groupby': ['folder'], 'groupby_custom': [], 'bulk_subject': 'Check_MK: Scheduled downtime for $COUNT_HOSTS$ hosts: $NOTIFICATIONCOMMENT})}, {'description': 'Time Drift', 'comment': 'Bulk notifications sent to all Check_MK users for NTP time drift issues.\n', 'docu_url': '', 'disabled': False, 'allow_disable': False, 'match_services': ['System Time'], 'match_timeperiod': 'WorkingHours', 'match_service_event': ['rw', 'rc', 'wr', 'wc', 'cr', 'cw', 'x'], 'contact_object': False, 'contact_all': False, 'contact_all_with_email': False, 'contact_groups': ['all'], 'notify_plugin': ('mail', {'elements': ['address', 'abstime', 'longoutput', 'graph'], 'notifications_with_graphs': 5}), 'bulk': ('always', {'interval': 180, 'count': 1000, 'groupby': ['state'], 'groupby_custom': []})}, {'description': 'Standard Host Notifications', 'comment': 'Standard set of host notifications sent to all Check_MK users.\n', 'docu_url': '', 'disabled': False, 'allow_disable': False, 'match_host_event': ['rd', 'dr', 'x'], 'contact_object': False, 'contact_all': False, 'contact_all_with_email': False, 'contact_groups': ['all'], 'notify_plugin': ('mail', {})}, {'description': 'Filesystem Free Space Notifications - SCCM DP Servers', 'comment': 'Free space notifications sent to Scott Carter.\n\nONLY includes free space notifications for SCCM DP servers\n', 'docu_url': '', 'disabled': False, 'allow_disable': False, 'match_hostgroups': ['sccmservers'], 'match_services': ['Filesystem', 'fs_'], 'match_timeperiod': 'WorkingHours', 'match_service_event': ['rw', 'rc', 'wr', 'wc', 'cr', 'cw', 'x'], 'contact_object': False, 'contact_all': False, 'contact_all_with_email': False, 'contact_groups': ['ScottCarter'], 'notify_plugin': ('mail', {'elements': ['address', 'abstime', 'longoutput', 'graph']})}, {'description': 'Filesystem Free Space Notifications', 'comment': 'Free space notifications sent to all Check_MK users.\n\nDoes NOT include free space notifications for SCCM DP servers\n', 'docu_url': '', 'disabled': False, 'allow_disable': False, 'match_hostgroups': ['adservers', 'appservers', 'exchangeservers', 'fileservers', 'firewalls', 'hypervservers', 'licenseservers', 'linnuxservers', 'miscdevs', 'miscservers', 'printers', 'revitservers', 'routers', 'No_OMSA', 'sqlservers', 'storage', 'switches', 'unassigned', 'vidcon', 'vmware', 'wap'], 'match_services': ['Filesystem', 'fs_'], 'match_timeperiod': 'WorkingHours', 'match_service_event': ['rw', 'rc', 'wr', 'wc', 'cr', 'cw', 'x'], 'contact_object': False, 'contact_all': False, 'contact_all_with_email': False, 'contact_groups': ['all'], 'notify_plugin': ('mail', {'elements': ['address', 'abstime', 'longoutput', 'graph']})}, {'description': 'Standard Service Notifications', 'comment': 'Standard set of notifications sent to all Check_MK users.\n\nThis includes:\nDisk failures for Promise and QNAP boxes\nAEC License availability\n', 'docu_url': '', 'disabled': False, 'allow_disable': False, 'match_services': ['AEC Licenses', 'BI_License_Servers', 'QNAP Disks'], 'match_timeperiod': 'WorkingHours', 'match_service_event': ['rw', 'rc', 'wr', 'wc', 'cr', 'cw', 'x'], 'contact_object': False, 'contact_all': False, 'contact_all_with_email': False, 'contact_groups': ['all'], 'notify_plugin': ('mail', {'elements': ['address', 'abstime', 'longoutput', 'graph']})}, {'description': 'BST10 Services', 'comment': '', 'docu_url': '', 'disabled': False, 'allow_disable': False, 'match_hosts': ['BST10', 'BSTDB10'], 'match_services': ['service_BSTGlobal_Transaction_Processor_Service', 'service_BSTGlobal_Reporting_Service', 'service_MSSQLSERVER', 'service_SQLServerReportingServices', 'service_BSTGlobal_Mobile_Private_Cache_(Redis)'], 'match_timeperiod': 'WorkingHours', 'contact_object': False, 'contact_all': False, 'contact_all_with_email': False, 'contact_groups': ['BST'], 'notify_plugin': ('mail', {})}, {'description': 'BSTVIR', 'comment': '', 'docu_url': '', 'disabled': False, 'allow_disable': False, 'match_services': ['service_BSTVIR'], 'match_timeperiod': 'WorkingHours', 'contact_object': False, 'contact_all': False, 'contact_all_with_email': False, 'contact_groups': ['all'], 'notify_plugin': ('mail', {})}, {'description': 'Dell OMSA Service Notifications', 'comment': 'Standard set of notifications sent to all Check_MK users.\n\nThis includes:\nDell OMSA issues (RAID/RAM/CPU failures, high temps, etc)\n\n', 'docu_url': '', 'disabled': False, 'allow_disable': False, 'match_services': ['Dell', 'Management Interface:'], 'match_timeperiod': 'WorkingHours', 'match_service_event': ['rw', 'rc', 'wr', 'wc', 'cr', 'cw', 'x'], 'contact_object': False, 'contact_all': False, 'contact_all_with_email': False, 'contact_groups': ['all'], 'notify_plugin': ('mail', {'elements': ['address', 'abstime', 'longoutput']}), 'bulk': ('always', {'interval': 60, 'count': 1000, 'groupby': ['host'], 'groupby_custom': [], 'bulk_subject': 'Check_MK: $COUNT_NOTIFICATIONS$ notifications for $COUNT_HOSTS$ hosts'})}, {'comment': '', 'match_service_event': ['rw', 'rr', 'rc', 'ru', 'wr', 'wc', 'cr', 'cw', 'ur', 'x'], 'description': 'Exchange Notifications', 'contact_groups': ['ScottCarter'], 'disabled': False, 'notify_plugin': ('mail', {'no_floating_graphs': True, 'elements': ['address', 'abstime', 'longoutput', 'graph']}), 'match_hostgroups': ['exchangeservers'], 'docu_url': '', 'contact_all': False, 'contact_object': False, 'allow_disable': False, 'contact_all_with_email': False, 'match_services': ['Exchange']}, {'description': 'Veeam Backup Jobs', 'comment': '', 'docu_url': '', 'disabled': True, 'allow_disable': True, 'match_services': ['VEEAM Job', 'Dell'], 'contact_object': False, 'contact_all': False, 'contact_all_with_email': False, 'contact_users': ['Teams'], 'notify_plugin': ('teams.py', ['https://<removed for privacy>'])}]