THIS IS A SCHEDULED EVENT Aug <var data-var='date'>31</var>, <var data-var='time'>20:00</var> - <var data-var='time'>20:30</var> MDT Aug <var data-var='date'>14</var>, <var data-var='time'>09:33</var> MDT Scheduled - MasterFax - Sunset End-of-Service ATAs (SN prefix: D) Purpose: Sunset MP202B devices as prerequisite of future security update. Systems Affected: CT Cloud Fax (MasterFax) Impact: Legacy MP202B ATAs will no longer be able to connect to our MasterFax servers after the maintenance window. If your ATA's serial number starts with "D" and you have not arranged temporary continued access through our Client Success team, please contact accountmanagement@calltower.com. Outage: No

OUT OF CYCLE MAINTENANCE

THIS IS A SCHEDULED EVENT Aug <var data-var='date'>23</var>, <var data-var='time'>22:00</var> - <var data-var='time'>22:30</var> MDT Aug <var data-var='date'>14</var>, <var data-var='time'>09:38</var> MDT Scheduled - NOAM CT Cloud Voice - Test CommPortal and SIP PS failover Purpose: Test failover between CT2CHIWAF01 and CT2DALWAF01 Systems Affected: CT Cloud Voice Impact: Users may need to log back into CommPortal and/or CT Cloud Communicator Outage: Yes

Aug <var data-var='date'>22</var>, <var data-var='time'>04:00</var> MDT Completed - The scheduled maintenance has been completed. Aug <var data-var='date'>21</var>, <var data-var='time'>22:00</var> MDT In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. Aug <var data-var='date'>14</var>, <var data-var='time'>09:36</var> MDT Scheduled - Reboot Call Manager Environment Purpose: Reboot all clusters and nodes inside clusters Systems Affected: Cisco Call Manager: Impact: Server Reboots of the Cisco Unified Communications Manager will occur. Your phone will re-register to the next server in the Server list. Calls in progress 'should' remain up until the call has ended. Phone will most likely re register multiple times during the MW time. This is expected behavior Outage: No NOAM CT Cloud August 2026 maintenance Purpose: Transfer CFS and EAS service for NOAM Meta from CHI to DAL Systems Affected: CT Cloud SIP and Voice Impact: New calls attempted during service transfer may fail to setup, calls in progress will not be affected. Any failed calls should be re-tried. Downtime will be 5 minutes or less while services are transferred to redundant servers for monthly maintenance. Impact: Jabber Clients will receive a Certificate Warning. Please be aware that this is expected behavior and all users will need to accept this before signing back in. Outage: Yes

Scheduled Maintenance

Aug <var data-var='date'>16</var>, <var data-var='time'>23:00</var> MDT Completed - The scheduled maintenance has been completed. Aug <var data-var='date'>16</var>, <var data-var='time'>22:00</var> MDT In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. Aug <var data-var='date'>14</var>, <var data-var='time'>09:28</var> MDT Scheduled - CT Cloud Voice - Renew legacy SSL certs Purpose: Renew legacy certs: - userchat.appiaservices.com (SMS for CT Cloud Voice) - userportal.appiaservices.com (Legacy CommPortal) Systems Affected: CT Cloud Voice users with SMS Impact: - Users may need to log back into CT Cloud Communicator. Downtime will be 5 minutes or less while the new certificate is loaded. Outage: Yes We apologize for the short notice.

Jul <var data-var='date'>21</var>, <var data-var='time'>12:00</var> MDT Completed - The scheduled maintenance has been completed. Jul <var data-var='date'>21</var>, <var data-var='time'>11:00</var> MDT In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. Jul <var data-var='date'>20</var>, <var data-var='time'>12:34</var> MDT Scheduled - Purpose: Patching and preventative maintenance on multiple systems. Systems Affected: CT Text: -CT Text Down Vendor Emergency Maintenance ***Possible Impact: The CT Text SMS service will be down due to emergency maintenance by the downstream vendor. This service could potentially be down for 1 hour and return to normal at 12:00 PM MDT. We apologize for the short notice.

Out-Of-Cycle Maintenance

Jul <var data-var='date'>18</var>, <var data-var='time'>04:00</var> MDT Completed - The scheduled maintenance has been completed. Jul <var data-var='date'>17</var>, <var data-var='time'>22:00</var> MDT In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. Jul <var data-var='date'>10</var>, <var data-var='time'>10:03</var> MDT Scheduled - PSTN / Global SIP (Sansay Infrastructure): - Moving Sansay’s from old HK2 Rack to new HK2 Rack. ***Possible Impact: Active calls on the Hong Kong Sansay will be terminated when the maintenance begins. For any customers with functional redundancy from the Hong Kong Sansay to another CallTower datacenter will be able to make and receive new calls via the redundant datacenter during the maintenance window. Outage: Yes PSTN / Global SIP (Sansay Infrastructure): - LAX Border Router Software Updates ***Possible Impact: Sansay customer calls may intermittently drop while updates are being performed and traffic is rerouted. Outage: No Cisco: - Security Update Expressway Clusters for CUCM ***Possible Impact: *Cisco Jabber/ MRA Phones, Users will experience a connectivity loss with their Jabber Client/Services and/or MRA Edge connection Phones. Outage: Yes Legacy OneStream Customers: - car1ff reload/Licensing update. ***Possible Impact: All legacy OneStream voice services will be down for a few minutes while the device is being reloaded. Outage: Yes

Jul <var data-var='date'>16</var>, <var data-var='time'>12:31</var> MDT Resolved - Microsoft has reported that they have implemented a fix for the issue affecting Dial by Name functionality for Microsoft Teams customers. Following the deployment of the fix, CallTower engineers have completed validation testing across multiple customer tenants and have confirmed that the service is functioning as expected. If you are still experiencing issues, please reach out to support@calltower.com. CallTower will be closing this master case and all associated cases. Jul <var data-var='date'>15</var>, <var data-var='time'>13:01</var> MDT Update - CallTower engineers continue to work with Microsoft to investigate the Dial by Name issue affecting some Teams customers. The issue remains under active review, and escalation efforts are ongoing as both teams analyze available diagnostic information. We will share additional updates as soon as new information becomes available and thank you for your patience while this investigation continues. *CallTower has opened a master case to investigate this issue as it has been reported by more than one CallTower customer. This issue may or may not directly affect your services and is currently under investigation. If you are affected, please report the issue to support@calltower.com. CallTower intends to post updates on status.calltower.com approximately every 60 minutes, unless identified otherwise. This issue is being investigated as a top priority. Jul <var data-var='date'>15</var>, <var data-var='time'>11:43</var> MDT Update - CallTower engineers continue to investigate the issue affecting Dial by Name functionality for a subset of Teams Operator Connect customers. We remain actively engaged with Microsoft and continue to escalate the matter to assist in identifying the underlying cause and restoring normal service as quickly as possible. *CallTower has opened a master case to investigate this issue as it has been reported by more than one CallTower customer. This issue may or may not directly affect your services and is currently under investigation. If you are affected, please report the issue to support@calltower.com. CallTower intends to post updates on status.calltower.com approximately every 60 minutes, unless identified otherwise. This issue is being investigated as a top priority. Jul <var data-var='date'>15</var>, <var data-var='time'>10:39</var> MDT Investigating - CallTower is investigating reports of the Dial by Name feature not working for some of our Operator Connect customers. We have opened a case with Microsoft to help investigate this issue. *CallTower has opened a master case to investigate this issue as it has been reported by more than one CallTower customer. This issue may or may not directly affect your services and is currently under investigation. If you are affected, please report the issue to support@calltower.com. CallTower intends to post updates on status.calltower.com approximately every 60 minutes, unless identified otherwise. This issue is being investigated as a top priority.

Dial by Name Function Failing

Jul <var data-var='date'>13</var>, <var data-var='time'>08:51</var> MDT Resolved - CallTower considers the issue resolved at this time. We will be closing this master case and all associated cases. Within three business days, an Official Root Cause Analysis (RCA) or a Preliminary RCA will be available and provided to customers upon request. Jul <var data-var='date'> 9</var>, <var data-var='time'>06:02</var> MDT Monitoring - CallTower engineers have completed remediation efforts and service appears to be restored, based on current monitoring and testing. We ask that affected customers please retest their services and confirm that normal functionality has been restored. If you continue to experience any issues, please contact CallTower Support and provide details of the impact so that our teams can investigate further. CallTower has opened a master case for this issue as it is affecting more than one CallTower customer. This issue may or may not directly affect your services. If you are affected, please report the issue to support@calltower.com. CallTower intends to post updates on status.calltower.com as any new information becomes available. Jul <var data-var='date'> 9</var>, <var data-var='time'>05:33</var> MDT Update - CallTower Network Engineers have identified a potential cause of the service disruption and are actively working to implement remediation measures. At this time, our engineers are focused on validating the identified cause and restoring full-service stability as quickly as possible. We are continuing to monitor the environment closely and are treating this issue as a top priority. CallTower has opened a master case for this issue as it is affecting more than one CallTower customer. This issue may or may not directly affect your services. If you are affected, please report the issue to support@calltower.com. CallTower intends to post updates on status.calltower.com approximately every 30 minutes, unless identified otherwise Jul <var data-var='date'> 9</var>, <var data-var='time'>05:00</var> MDT Identified - CallTower engineers are continuing their efforts to isolate and restore services in EMEA for all affected customers. CallTower has opened a master case for this issue as it is affecting more than one CallTower customer. This issue may or may not directly affect your services. If you are affected, please report the issue to support@calltower.com. CallTower intends to post updates on status.calltower.com approximately every 30 minutes, unless identified otherwise Jul <var data-var='date'> 9</var>, <var data-var='time'>04:28</var> MDT Update - Microsoft Teams and Zoom customers in EMEA are receiving failures when attempting outbound calls. Calltower's voice network engineers have been engaged and are working diligently to restore services in EMEA. CallTower has opened a master case to investigate this issue as it has been reported by more than one CallTower customer. This issue may or may not directly affect your services and is currently under investigation. If you are affected, please report the issue to support@calltower.com. CallTower intends to post updates on status.calltower.com approximately every 30 minutes, unless identified otherwise. This issue is being investigated as a top priority. Jul <var data-var='date'> 9</var>, <var data-var='time'>03:57</var> MDT Investigating - CallTower has opened a master case to investigate this issue as it has been reported by more than one CallTower customer. This issue may or may not directly affect your services and is currently under investigation. If you are affected, please report the issue to support@calltower.com. CallTower intends to post updates on status.calltower.com approximately every 30 minutes, unless identified otherwise. This issue is being investigated as a top priority.

EMEA outbound calls failing

Jul <var data-var='date'>12</var>, <var data-var='time'>23:00</var> MDT Completed - The scheduled maintenance has been completed. Jul <var data-var='date'>12</var>, <var data-var='time'>22:00</var> MDT In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. Jul <var data-var='date'>10</var>, <var data-var='time'>11:31</var> MDT Scheduled - Purpose: Patching and preventative maintenance on multiple systems. Systems Affected: CT Cloud Voice: - Meta WAFs - Modify WAF Inspection ***Possible Impact: Users may need to log back into CommPortal and/or CT Cloud Communicator

Jul <var data-var='date'> 7</var>, <var data-var='time'>17:10</var> MDT Completed - The scheduled maintenance has been completed. Jul <var data-var='date'> 7</var>, <var data-var='time'>15:45</var> MDT Scheduled - As part of our ongoing efforts to protect customers from toll fraud, CallTower is expanding the list of high-risk calling destinations to include select exchanges in Alaska and Montana. Customers who do not have high-risk calling enabled on their account may be unable to place calls to certain destinations identified as having an elevated fraud risk. If you are unable to complete calls to a destination and believe there is a legitimate business need, please contact CallTower Support. Our team can help determine whether fraud-prevention controls are affecting call completion and discuss available options.

Service Update: High-Risk Calling Destination Changes

May <var data-var='date'>16</var>, <var data-var='time'>04:00</var> MDT Completed - The scheduled maintenance has been completed. May <var data-var='date'>15</var>, <var data-var='time'>22:00</var> MDT In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. May <var data-var='date'> 8</var>, <var data-var='time'>09:22</var> MDT Scheduled - Cisco: - Update mra.ct450.com and mra-02.ct450.com latest release ***Possible Impact: Cisco Edge Phones: CallTower will be loading a Public Certificate to all Edge servers for mra.ct450.com and mra02.ct450.com . Phones are expected to be down for no more than a few minutes and should connect as usual once servers are restarted. Outage: No Webex: - car1.lon & car1.fra cleanup ***Possible Impact: Webex customers may experience brief interruption of active calls when changes are made Outage: No Fax: - MasterFax - Isolate MP202B traffic ***Possible Impact: Some MasterFax ATAs may experience a brief interruption as devices reconnect to our Fax Servers during the Maintenance Window Outage: Yes ATL Meta Customers: - ATL Meta - May 2026 maintenance ***Possible Impact: New calls may fail to setup while services are failed over during maintenance. Calls in progress will not be affected. Downtime will be 30 seconds or less. Outage: Yes CT Cloud Communicator: - CT Cloud Communicator Mobile 3.21.61 ***Possible Impact: CT Cloud Communicator Mobile users will be forced to upgrade to v3.21.61 to continue using the application. As a reminder, users currently using CTCC mobile pre-3.21.61 must perform a one-time manual upgrade, or in-app upgrades will fail. Additional information about this is available in uc.solutions. Outage: No

Apr <var data-var='date'>29</var>, <var data-var='time'>12:59</var> MDT Resolved - CallTower Support has confirmed resolution of the Five9-related issues that were impacting call delays, audio issues, browser speed, and connection issues to Five9. The issue was addressed in coordination with Five9 Engineering, and services are operating normally at this time. CallTower will be closing this master case and all associated cases. Within three business days, an Official Root Cause Analysis (RCA) or a Preliminary RCA will be available and provided to customers upon request. Apr <var data-var='date'>29</var>, <var data-var='time'>11:22</var> MDT Investigating - CallTower Support has received reports of issues impacting some Five9 customers. Users may experience call delays, Audio issues, intermittent slow browser speed, and connection issues to Five9. CallTower support is currently investigating with Five9 engineering to mitigate and resolve these issues. *CallTower has opened a master case to investigate this issue as it has been reported by more than one CallTower customer. This issue may or may not directly affect your services and is currently under investigation. If you are affected, please report the issue to support@calltower.com. CallTower intends to post updates on status.calltower.com approximately every 60 minutes, unless identified otherwise. This issue is being investigated as a top priority.

Five9 Service Degradation – Call Performance and Connectivity Issues

Mar <var data-var='date'>23</var>, <var data-var='time'>00:00</var> MDT Completed - The scheduled maintenance has been completed. Mar <var data-var='date'>22</var>, <var data-var='time'>20:00</var> MDT In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. Mar <var data-var='date'>17</var>, <var data-var='time'>14:27</var> MDT Scheduled - Purpose: Patching and preventative maintenance on multiple systems. Systems Affected: CT Cloud Voice: -ATL Meta - March 2026 maintenance ***Possible Impact: New calls may fail to set up while services are failed over during maintenance. Calls in progress will not be affected. Downtime will be 30 seconds or less.

Mar <var data-var='date'>21</var>, <var data-var='time'>04:00</var> MDT Completed - The scheduled maintenance has been completed. Mar <var data-var='date'>20</var>, <var data-var='time'>22:00</var> MDT In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. Mar <var data-var='date'>13</var>, <var data-var='time'>11:32</var> MDT Scheduled - Purpose: Patching and preventative maintenance on multiple systems. Systems Affected: Fax: -MasterFax and CT Cloud Fax - General Server Maintenance ***Possible Impact: Customers will experience interruptions to both MasterFax and CT Cloud Fax services during the Maintenance Window Cisco: -Update mra.ct450.com and mra02.ct450.com Latest Release ***Possible Impact: Cisco Edge Phones: CallTower will be loading a Public Certificate to all Edge servers for mra.ct450.com and mra02.ct450.com . Phones are expected to be down for no more than a few minutes and should connect as usual once servers are restarted.

Mar <var data-var='date'> 2</var>, <var data-var='time'>13:15</var> MST Resolved - CallTower Support has received positive confirmation from affected customers, and the CT Cloud Communicator Mobile issue is considered resolved. CallTower will be closing this master case and all associated cases. Within three business days, an Official Root Cause Analysis (RCA) or a Preliminary RCA will be available and provided to customers upon request. Mar <var data-var='date'> 2</var>, <var data-var='time'>12:37</var> MST Monitoring - Based on vendor guidance, CallTower Engineering completed a configuration change designed to address the CT Cloud Communicator Mobile issue. CallTower Support will continue to monitor the environment to confirm the issue is fully resolved. CallTower has opened a master case for this issue as it is affecting more than one CallTower customer. This issue may or may not directly affect your services. If you are affected, please report the issue to support@calltower.com. CallTower intends to post updates on status.calltower.com approximately every 30 minutes, unless identified otherwise. Mar <var data-var='date'> 2</var>, <var data-var='time'>11:32</var> MST Update - CallTower Engineering continues to partner with the vendor on log and diagnostic review. The issue has been isolated to an affected system, and investigation is ongoing. CallTower has opened a master case for this issue as it is affecting more than one CallTower customer. This issue may or may not directly affect your services. If you are affected, please report the issue to support@calltower.com. CallTower intends to post updates on status.calltower.com approximately every 30 minutes, unless identified otherwise. Mar <var data-var='date'> 2</var>, <var data-var='time'>10:56</var> MST Update - CallTower Engineering remains engaged with the vendor and is providing logs and diagnostic information as part of the ongoing resolution process. CallTower has opened a master case for this issue as it is affecting more than one CallTower customer. This issue may or may not directly affect your services. If you are affected, please report the issue to support@calltower.com. CallTower intends to post updates on status.calltower.com approximately every 30 minutes, unless identified otherwise. Mar <var data-var='date'> 2</var>, <var data-var='time'>10:25</var> MST Identified - The issues affecting CT Cloud Communicator Mobile have been identified as vendor-related. CallTower engineers are actively working with the vendor to determine and implement a resolution. CallTower has opened a master case for this issue as it is affecting more than one CallTower customer. This issue may or may not directly affect your services. If you are affected, please report the issue to support@calltower.com. CallTower intends to post updates on status.calltower.com approximately every 30 minutes, unless identified otherwise. Mar <var data-var='date'> 2</var>, <var data-var='time'>09:52</var> MST Investigating - CallTower Support is actively investigating multiple reports of inbound and outbound call failures and login issues with CT Cloud Communicator Mobile but has not identified/confirmed there is an issue on our network or with our services. CallTower has opened a master case to investigate this issue as it has been reported by more than one CallTower customer. This issue may or may not directly affect your services and is currently under investigation. If you are affected, please report the issue to support@calltower.com. CallTower intends to post updates on status.calltower.com approximately every 30 minutes, unless identified otherwise. This issue is being investigated as a top priority.

CT Cloud Communicator Mobile Inbound calls, Outbound calls, and Login Issues

Mar <var data-var='date'> 1</var>, <var data-var='time'>23:00</var> MST Completed - The scheduled maintenance has been completed. Mar <var data-var='date'> 1</var>, <var data-var='time'>21:00</var> MST In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. Feb <var data-var='date'>27</var>, <var data-var='time'>10:33</var> MST Scheduled - Purpose: Patching and preventative maintenance on multiple systems. Systems Affected: CT Cloud Voice: -CT Cloud Maintenance - March 2026 ***Possible Impact: New calls may fail to set up while services are failed over during maintenance. Calls in progress will not be affected. Downtime will be 30 seconds or less.

Feb <var data-var='date'>23</var>, <var data-var='time'>02:00</var> MST Completed - The scheduled maintenance has been completed. Feb <var data-var='date'>22</var>, <var data-var='time'>20:00</var> MST In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. Feb <var data-var='date'>13</var>, <var data-var='time'>10:24</var> MST Scheduled - CT Cloud Maintenance - February 2026 Purpose: Upgrade CHI/DAL Meta from 9.6.70 to 9.7.20 Systems Affected: CT Cloud SIP CT Cloud Voice Impact: New calls may fail to setup while services are failed over during maintenance. Calls in progress will not be affected. Downtime will be 30 seconds or less. Outage: Yes NOAM Meta 9.7 upgrade Purpose: Upgrade CHI/DAL Meta to 9.7.20 SU13 for security and stability improvements. Systems Affected: CT Cloud SIP CT Cloud Voice Impact: New calls may fail to setup while services are failed over during maintenance. Calls in progress will not be affected. Downtime will be 30 seconds or less. Outage: Yes

Feb <var data-var='date'>21</var>, <var data-var='time'>03:00</var> MST Completed - The scheduled maintenance has been completed. Feb <var data-var='date'>20</var>, <var data-var='time'>21:00</var> MST In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. Feb <var data-var='date'>13</var>, <var data-var='time'>10:22</var> MST Scheduled - ATL Data Center Core Switch Maintenance Purpose: replace the main core switch in the ATl Data Center Systems Affected: Cisco Jabber Cisco Voice Impact: Cisco Jabber: Jabber clients may experience intermittent connectivity or login issues as servers are shutdown and failover to redundant data centers occurs. Cisco phone registration: Cisco phones may temporarily unregister as they reregister with servers in redundant data centers. Outage: No MasterFax & CT Cloud Fax - General Server Maintenance Purpose: Monthly server maintenance: remove old/stuck faxes, reboot servers updating Wireshark Systems Affected: MasterFax CT Cloud Fax Impact: Customers will experience interruptions to both MasterFax and CT Cloud Fax services during the Maintenance Window Outage: Yes Update Jabber certificate for collaborate-atl.ct450.com Purpose: Calltower will be upgrading the Edge servers for Jabber. Systems Affected: Cisco Jabber Impact: Users will experience a connectivity loss with their Jabber Client/Services. Outage: Yes

Feb <var data-var='date'>20</var>, <var data-var='time'>12:15</var> MST Resolved - Some CallTower customers may have briefly experienced issues with Intermedia Contact Center Voice and login. The issue was identified as an Intermedia service outage and has since been resolved. Update from Intermedia: Intermedia Engineering teams identified the root cause as a Cloudflare service disruption that affected connectivity to certain Intermedia services. The third-party provider has since restored service, and Intermedia has verified that Email, Contact Center, and Voice services are fully operational. If any issues persist, customers are advised to contact Intermedia Support for assistance. CallTower will be closing this master case and all associated cases. Within three business days, an Official Root Cause Analysis (RCA) or a Preliminary RCA will be available and provided to customers upon request.

Intermedia Contact Center Issues Logging In, Inbound and Outbound Voice Calling Failures

Feb <var data-var='date'>12</var>, <var data-var='time'>19:00</var> MST Completed - The scheduled maintenance has been completed. Feb <var data-var='date'>12</var>, <var data-var='time'>16:00</var> MST In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. Feb <var data-var='date'> 9</var>, <var data-var='time'>16:04</var> MST Scheduled - CallTower EMEA Layer 2 migration Purpose: Migrating connections for Five9 endpoints. Systems Affected: Five9 Impact: Services will be hard down as we migrate from old to new circuits; during failover testing users may experience intermittent issues. Outage: Yes

Feb <var data-var='date'>11</var>, <var data-var='time'>01:00</var> MST Completed - The scheduled maintenance has been completed. Feb <var data-var='date'>10</var>, <var data-var='time'>22:00</var> MST In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. Feb <var data-var='date'> 9</var>, <var data-var='time'>16:03</var> MST Scheduled - CallTower US Layer 2 migration Purpose: Migrating connections for Five9 endpoints. Systems Affected: Five9 Impact: Services will be hard down as we migrate from old to new circuits; during failover testing users may experience intermittent issues. Outage: Yes

Feb <var data-var='date'> 4</var>, <var data-var='time'>10:33</var> MST Resolved - Microsoft is now reporting that the issue affecting Teams users ability to toggle call queues has been resolved. Microsoft’s final posting is included below. Issue ID: TM1226887 Affected services: Microsoft Teams Status: Service restored Issue type: Advisory Start time: Feb 4, 2026, 2:30 AM MST End time: Feb 4, 2026, 9:22 AM MST User impact Users may have been unable to toggle call queues on or off in the Microsoft Teams web or desktop client. More info As a workaround, users may have been able to use the Microsoft Teams mobile app to toggle call queues as expected. Additionally, admins may have been unable to make changes to call queues, auto attendants, and holidays within the Microsoft Teams admin center. Scope of impact Some users hosted in the North America region attempting to toggle call queues in the Microsoft Teams web or desktop client may have been impacted. Additionally, admins making changes to call queues, auto attendants, and holidays in the Microsoft Teams admin center may also have been affected. Root cause A code change contained within a recent service update was causing requests to be sent to an incorrect URL, resulting in impact. Next steps - We're reviewing our update procedures to understand why impact to call queues wasn't caught during the testing phase. This will allow us to drive service improvements by proactively identifying similar issues in the future and improve our update testing processes. Current status Feb 4, 2026, 10:08 AM MST We've reverted the offending service update and confirmed through monitoring service health telemetry that the impact has been remediated. This is the final update for the event. * CallTower will be closing this master case and all associated cases. Feb <var data-var='date'> 4</var>, <var data-var='time'>09:27</var> MST Investigating - Microsoft has reported issues with opting into Teams call queues. Microsoft has released an official service health alert for this issue (TM1226887), which is included below. Calltower has identified a workaround for the issue by toggling off the option "Call agents can opt out of taking calls" in the Teams Admin Center. Microsoft also reports that using the Teams application on mobile is a valid workaround. Microsoft's Posting (TM1226887) Issue ID: TM1226887 Affected services: Microsoft Teams Status: Service degradation Issue type: Advisory Start time: Feb 4, 2026, 9:10 AM MST User impact Users may be unable to toggle call queues on or off in the Microsoft Teams web or desktop client. More info As a workaround, users may be able to use the Microsoft Teams mobile app to toggle call queues as expected. Scope of impact Some users hosted in the North America region attempting to toggle call queues in the Microsoft Teams web or desktop client may be impacted. Root cause A code change contained within a recent service update is causing request to be sent to an incorrect URL, resulting in impact. Current status Feb 4, 2026, 9:11 AM MST We've identified that a code change contained within a recent service update is causing requests to be sent to an incorrect URL, resulting in impact. We're reverting the offending service update as a potential remediation action, and anticipate this process will complete by our next scheduled communications update. Next update by: Wednesday, February 4, 2026 at 11:00 AM MST *CallTower has opened a master case to investigate this issue as it has been reported by more than one CallTower customer. This issue may or may not directly affect your services and is currently under investigation. If you are affected, please report the issue to support@calltower.com. CallTower intends to post updates on status.calltower.com approximately every 30 minutes, unless identified otherwise. This issue is being investigated as a top priority.

Microsoft Teams Call Queue Failures

Jan <var data-var='date'>29</var>, <var data-var='time'>19:30</var> MST Completed - The scheduled maintenance has been completed. Jan <var data-var='date'>29</var>, <var data-var='time'>19:00</var> MST In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. Jan <var data-var='date'>29</var>, <var data-var='time'>15:23</var> MST Scheduled - Purpose: Patching and preventative maintenance. Systems Affected: CT Cloud SIP: -Remove Transcoding from IPAuth Adjacency ***CallTower will be disabling support for transcoding. Customers need to ensure that they support G.711, G.729, and/or RFC 2833.

Jan <var data-var='date'>26</var>, <var data-var='time'>04:00</var> MST Completed - The scheduled maintenance has been completed. Jan <var data-var='date'>25</var>, <var data-var='time'>22:00</var> MST In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. Jan <var data-var='date'>16</var>, <var data-var='time'>10:20</var> MST Scheduled - CT Cloud Voice - January 2026 maintenance Purpose: Renew APNS certs for AMS, EAS and Perimeta Systems Affected: CT Cloud Voice Impact: Users with CT Cloud Communicator for iOS will need to log back into the application Outage: Yes CT Cloud Communicator - Mandatory update to v3.21.60 Purpose: This version removes CT Cloud Meeting, which has been decommissioned (and no longer functions) 2. Security updates and bug fixes Systems Affected: CT Cloud Voice Impact: Users with CT Cloud Communicator will be forced to upgrade to v3.21.60. Desktop users will be notified in-app if they are not already using v3.21.60 and forced to upgrade to v3.21.60 before they can continue using the app. ***Mac OS users: If CTCC hangs or freezes after update, follow these steps: 1. Uninstall the app from Applications 2. Open Finder and navigate to Go -> Go to folder -> type "~/Library/ApplicationSupport and press go. Remove anything with "CT Cloud" in the name. 3. Open Finder and navigate to Go -> Go to folder -> type "~/Library/Caches and press go. Remove anything with "CT Cloud" in the name. 4. Install CTCC 3.21.60 from CommPortal Mobile users can check and update their current version in the respective app store on their phone. These users will be prompted and forced to upgrade to v3.21.60 before they can continue using the app. Outage: No

Jan <var data-var='date'>24</var>, <var data-var='time'>04:00</var> MST Completed - The scheduled maintenance has been completed. Jan <var data-var='date'>23</var>, <var data-var='time'>22:00</var> MST In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary. Jan <var data-var='date'>16</var>, <var data-var='time'>10:17</var> MST Scheduled - Upgrade collaborate.ct450.com to V15.3.2 Purpose: Upgrade of collaborate.ct450.com which is 15.3 to 15.3.2 . According to Cisco there are bug fixes that are addressed Systems Affected: *Cisco Jabber Impact: Calltower will be upgrading the Edge servers for Jabber. Users will experience a connectivity loss with their Jabber Client/Services. Outage: Yes Regen CUPs Server Certs Clusters 00,02 and 10 Purpose: Calltower will be updating certificates for the CIsco CUPS servers for Jabber. Systems Affected: *Cisco Jabber Impact: Jabber Clients will receive a Certificate Warning. Please be aware that this is expected behavior and all users will need to accept this before signing back in. Outage: No HCS Server Certificate Renewal - Reboot Purpose: Server Reboots of the HCS Cisco Unified Communications Manager will occur. Systems Affected: *Cisco Call Manager - HCS Impact: User phones will re-register to the next server in the Server list. Calls in progress 'should' remain up until the call has ended. Phone will most likely re register multiple times during the MW time. This is expected behavior. Outage: No MasterFax & CT Cloud Fax - General Server Maintenance Purpose: Monthly server maintenance: remove old/stuck faxes, reboot servers Systems Affected: *MasterFax & CT Cloud Fax Impact: Customers will experience interruptions to both MasterFax and CT Cloud Fax services during the Maintenance Window Outage: Yes

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