Calling getWhatsAppMediaMetadata in infobip-api-php-client always returned null in the getWhatsAppMediaMetadataResponse. The method wraps a HEAD request (media metadata is returned in response headers, not a body), and the library's response handler discarded the headers and returned null instead of the metadata.
infobip-api-php-client getWhatsAppMediaMetadata returns null
The library did not model HEAD-request responses properly and dropped the metadata headers. The maintainers fixed it in version 6.2.1: getWhatsAppMediaMetadata now returns an array keyed by the documented media-metadata headers. Upgrade infobip-api-php-client to 6.2.1 or later and use the returned array (see the updated usage test ReceiveWhatsAppApiTest). The reporter confirmed the fix works.
Source: https://github.com/infobip/infobip-api-php-client/issues/67
Source: https://github.com/infobip/infobip-api-php-client/issues/67