Microsoft has announced significant changes to the allowed size and count of values for various Exchange properties. These alterations will be implemented in two phases between late September 2024 and late November 2024. Here’s a detailed breakdown of these changes and their implications for your organization.
Summary of Exchange Property Limits Update
Microsoft is implementing changes to the allowed size and count of values for various Exchange properties. These changes are set to occur in two phases: between late September 2024 and late November 2024. Below are the details of these changes and how they might affect your organization.
Phase 1: Starting in Late September 2024
Affected Properties and New Limits
| Property | Max Length (characters) | Max Count (entities) |
|---|---|---|
| CloudMSExchUCVoiceMailSettings | 1123 | 20 |
| MSExchArchiveName | 512 | 20 |
| MSExchResourceMetadata | 1024 | 20 |
| MSExchSenderHintTranslations | 500 | 20 |
| ExchangeResources | 1024 | 20 |
Phase 2: Starting in Late November 2024
Affected Properties and New Limits
| Property | Max Length (characters) | Max Count (entities) |
|---|---|---|
| CloudMSRtcPolicyAssignments | 128 | 45 |
| MSExchResourceSearchProperties | 1024 | 35 |
| CloudMSExchUserHoldPolicies | 40 | 1150 |
| MSExchExtensionCustomAttribute1 | 2048 | 750 |
| MSExchExtensionCustomAttribute2 | 2048 | 750 |
| MSExchExtensionCustomAttribute3 | 2048 | 400 |
| MSExchExtensionCustomAttribute4 | 2048 | 400 |
| MSExchExtensionCustomAttribute5 | 2048 | 250 |
| ValidationError | 948000 | 10 |
| ProxyAddresses | 1123 | 1200 |
Clarification on ProxyAddresses Limits
Microsoft clarified the limits for the attribute proxyAddresses to a fellow Reddit user. This attribute will likely be the main pain point for most organizations. Here’s Microsoft’s response:
“The advisory MC884017 specifies that the proxyAddresses attribute has a maximum length of 1123 characters and a maximum count of 1200 entries. Here’s the clarification:
- Maximum Length of 1123 Characters: This refers to the total length of all the addresses combined in the
proxyAddressesattribute. It means that the sum of the lengths of all the email addresses and aliases cannot exceed 1123 characters. - Maximum Count of 1200 Entries: This means you can have up to 1200 unique addresses (aliases) in the
proxyAddressesattribute.
So, you can have up to 1200 unique addresses, but the combined length of all these addresses must not exceed 1123 characters.”- Source
Impact on Your Organization
- Exceeded Limits: If any of these properties exceed the new limits, you will not be able to add new values or update existing values beyond the specified constraints.
- Policy Enforcement: These limits will be enforced beginning in the specified timeframes for each phase.
Conclusion
By being proactive about these changes, you can ensure that your organization remains compliant and avoids any disruptions to your Exchange services. Review your current configurations, plan necessary adjustments, and update your internal processes to comply with these new limits. Keep your team informed and prepared for these upcoming changes.
You can view more details and stay updated on these changes by visiting the Microsoft 365 admin center.
Source: Microsoft Admin Center