For reference, the performance counters in 7669 are:

EAS Sessions
EWS Sessions
IMAP Sessions
Messages Received
LDAP Sessions
MAPI Sessions
Messages in Spam Quarantine
Messages in Virus Quarantine
Messages Sent
POP Retrieval Sessions
POP Sessions
SMTP-In Sessions
SMTP-Out Sessions
Messages In Spool
Throttled Accounts
Throttled Domains
Webmail Sessions
XMPP Sessions

The performance counters we had in 7642 (and before) are:

Total Active Tcp Connections
Connections From BlackListed IP addresses
ClamAV Active Connections
ClamAV Failed Connections
ClamAV New Connections
Cyren Spam Bulk
Cyren Spam Confirmed
Cyren Spam Suspected
Cyren Spam Unknown
Cyren Virus Level High
Cyren Virus Level Medium
Cyren Virus Level No Virus
Cyren Virus Level Unknown
Cyren Virus Level Virus
CPU
DiskSpace
DiskSpaceFree
DiskSpaceFreePercent
DOS Violations
GreyListing Allowed Connections
GreyListing Blocked Connections
GreyListing Total Connections
Handles
Email Harvesting Violations
IMAP Active Sessions
IMAP Bad Commands
IMAP In Bandwidth
IMAP Blocked Connections
IMAP New Connections
IMAP Sessions
IMAP Terminations
Incoming Messages
Internal Spammer Violations
Memory
Message Sniffer Spam Confirmed
Message Sniffer Not Spam
New Incoming TCP Connections
Nonpaged Memory
Outgoing Messages
POP Active Sessions
POP Bad Commands
POP In Bandwidth
POP Blocked Connections
POP New Connections
POP Sessions
POP Terminated Connections
SmarterMail Process Threads
SMTP In Active Sessions
SMTP In Bad Commands
SMTP In Bandwidth
SMTP In Blocked Connections
SMTP In New Connections
SMTP In Terminated Connections
SMTP Out Active Sessions
SMTP Out Bandwidth
SMTP Out Failed Connections
SMTP Out New Connections
SMTP Out Terminated Connections
SMTP Sessions
SpamAssassin Active Connections
SpamAssassin Failed Connections
SpamAssassin New Connections
Spam High Messages
Spam Low Messages
Spam Medium Messages
Total Spam Messages
Outgoing Spam Messages Blocked
Messages In Spool
Virus Count
Connections From WhiteListed IP addresses
XMPP Blocked Connections

Scarab, you are correct that their was a change (simplification) to the performance counters.  This was included in the Build 7661 release:

Robert,

Totally missed that in the Release Notes. Now I at least know that I have to update all my Zabbix Checks and Triggers accordingly going forward. Thank you.