You can download this HotFix from TIBCO Support Portal (https://support.tibco.com). You will need to provide your TIBCO Support Portal credentials. Once logged in you can then download the hotfix by selecting the "Downloads" -> "HotFixes" option. Then navigate to respective folders -
AvailableDownloads/_Additional_Products/APIExchange/2.2.1/TIB_api-exchange-gateway_2.2.1_hotfix06
AvailableDownloads/_Additional_Products/APIExchange/2.2.1/TIB_api-exchange-manager_2.2.1_hotfix06

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Closed Issues in 2.2.1_HF-006 Gateway  (This Release)

ASG-8095
Provided Global Variable to support specific SSL Server Protocols with ConfigUI

ASG-8094
Provided Global Variable to support specific list of Ciphers with ConfigUI

ASG-8093
OAuth Client Adapter failed authentication and returned Endpoint error, 
"unauthorized_client, Invalid client credential"

ASG-8040
Provided option to override "Server" standard attribute/Response Header for embedded 
Tomcat (nativeHTTP Channel)
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Closed Issues in 2.2.1_HF-006 Manager (This Release)

There are no issues that were fixed in API Exchange Manager in 2.2.1_HF-006 release.
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