How message statuses (delivered, read) are assigned

Status checkmarks (delivered, read) are placed at the moment the message is sent — that is, in the same second after sending — regardless of whether the message has been delivered. Delivery often doesn't happen instantly because the person may be "offline" at the time. The program sends the message; delivery is handled by WhatsApp on its servers. As soon as the person comes online, the message is delivered. If the broadcasting account is banned, status information is no longer available, but as a rule all sent messages do reach active WhatsApp users.

Message statuses (delivered, read) are meant for general information: don't jump to conclusions based on these fields.

The OK_IN_BATCH status means the same as OK (i.e., sent) and additionally that some messages in this batch were delivered.

For example, if we send 10 at a time and at least one of those 10 messages is delivered, all 10 messages get the OK_IN_BATCH status. This means they are more likely to have been delivered, even if the statuses couldn't be collected. Resending messages to those numbers should be the lowest priority.