Error: pq: operator class “gin_trgm_ops” does not exist for access method “gin”

My lora-app-server has been working for a couple of weeks but suddently failed to start today. Granted, I have tried to install gpsd, cmaker and mbpoll on my Rpi 3B+ which holds the loraserver. I don’t know whehter that created some conflicts or not. But I uninstalled those tools but it does not help. The journalctl log shows the following error message:

May 03 13:34:57 ttn-gateway lora-app-server[1761]: time=“2018-05-03T13:34:57-07:00” level=fatal msg=“applying migrations error: pq: operator class “gin_trgm_ops” does not exist for access method “gin” handling 0027_global_search.sql”

Job grep on lora lists lora related job:
ttn@ttn-gateway:~ $ ps -aef | grep lora
gateway+ 605 1 0 13:11 ? 00:00:01 /usr/bin/lora-gateway-bridge
loraser+ 1361 1 0 13:21 ? 00:00:06 /usr/bin/loraserver
postgres 1372 423 0 13:21 ? 00:00:14 postgres: 9.6/main: loraserver_ns loraserver_ns ::1(50900) idle

Does anyone see such a problem before? Please help.

-Ming

Never mind. I found the solution in brocaar’s 0.19.0 release note: https://forum.loraserver.io/t/release-lora-app-server-0-19-0/1089