@thefy You can refer to the following documentation https://experienceleague.adobe.com/docs/deliverability-learn/deliverability-best-practice-guide/additional-resources/guidance-around-changes-to-google-and-yahoo.html 

@MarketerDev Spam complaints fall into the hard bounce suppression category and are excluded from the message send out. 

You can check this related thread https://experienceleaguecommunities.adobe.com/t5/journey-optimizer-questions/capture-information-from-a-form-on-a-landing-page/m-p/640717/highlight/true#M1135 

From the example shared, it is from an experience event. In your case, if you have an array of objects, you can refer to the attributes of the object (referred as zzz) as a filter using the syntax, (say for example, currentDataPackField.zzz== 'yyy' )

You can log this as an enhancement with the customer care team. Otherwise, you can leverage subscription lists if the form fields are checkboxes (say for example) and then with in the email designer, check for segment membership and accordingly personalize. Reference - https://experienceleague.adobe...

You won't be able to iterate if it is an array of strings / integers etc., you will have to access the respective index position. If it is an array of objects, you can filter by referring to example 3 in the documentation shared in the earlier thread   

1) you need to add the array in the Experience platform data source. Reference - https://experienceleague.adobe.com/docs/journey-optimizer/using/configuration/configure-journeys/data-source-journeys/about-data-sources.html?lang=en  2) and then leverage collection management functions to access the a...

@d_G_n111 Can you update the cacheDuration as following in the custom authentication payload and see if that works ?"cacheDuration":{"expiryInResponse":"json://expires_in","timeUnit": "hours"}

@trojan_horse you can create a batch segment leveraging the attributes from message feedback event schema and accordingly suppress it, within the journey.This schema / dataset contains the message delivery logs.

@akwankl This expression works.substr('https://www.testsite.com?identifier=12345', (indexOf('https://www.testsite.com?identifier=12345', 'identifier='))+11)