Files and [new] Notes (2 separate related lists) are successors for this:
Salesforce1 supports documents that are uploaded through the Files action OR through Chatter. Documents and any attachments uploaded through the Notes and Attachments section on a record list view aren't guaranteed to be accessible in Salesforce1
Support for notes, documents, files and attachments in Salesforce1
You can also set Files uploaded to the Attachments related list on records are uploaded as Salesforce Files, not as attachments
for compatibility - read more