Update on Chaengwattana TM30 mail-ins... I mailed in a TM30 application for my wife and son on 26 July (EMS both ways). I got the receipt back today, 5 September. As we took a holiday in Pattaya in August, I mailed in another TM30 on 19 August, so still waiting for that one.
TLDR : Answer Summary
The TM30 mail-in application process is showing signs of improvement, with users reporting quicker processing times compared to previous experiences. For example, one user successfully received a TM30 application receipt within about 40 days, while another noted their application was acknowledged as delivered but still pending. Others have remarked on reduced mail backlogs at processing centers.