If you notice PPRs (Passport Request letters) being issued for application series numbers close to yours, while your own file shows no update, don't read too much into the sequence:
- There's nothing to conclude solely from a file series/reference number. Other applicants with similarly close (and even earlier) series numbers report being pending as well, so a nearby number getting a PPR doesn't reliably predict your own timeline.
- Processing order isn't strictly sequential by file series. Various factors (individual file complexity, additional document requests, visa office workload) affect the order applications get processed in, beyond just when they were received.
The practical takeaway: use file series numbers as a very rough, unreliable signal at best — they're not a dependable way to estimate how close you are to a decision.