Hey there!
I just wrote a script that fetches data from the AQS new pages endpoint https://wikimedia.org/api/rest_v1/#!/Edited_pages_data/get_metrics_edited_pages_new_project_editor_type_page_type_granularity_start_end in order to prepare the our monthly health metrics (T199459 https://phabricator.wikimedia.org/T199459).
However, it seems like that endpoint doesn't yet have monthly data for September. For example, a query for Commons with a start of July 1 and and an end of October 1 https://wikimedia.org/api/rest_v1/metrics/edited-pages/new/commons.wikimedia.org/all-editor-types/content/monthly/20180701/20181001 returns only data for July and August. What's the schedule for updating this data?
To be honest, I feel pretty frustrated by this. Wikistats 1 generates data on content pages with a delay of 10-15 days after the end of the month, which has made it difficult for us to provide timely metrics to executives and the board. I had assumed (to a degree that I didn't even check) that by switching to this API, we would instead only have to deal with the delay in generating the mediawiki_history snapshot (5-7 days after the end of the month). But that doesn't seem to be the case.