On Synology DS with SSODS 3.15, armv5tejl-linux

with new convert.conf (rev. 24410 and newer) I'm not able to play any flac files. Server.log is full of errors:

/volume1/SSODS/bin/sox stio: Unknown output file format for '-':  File type `flac' is not known

The cause is probably in 

flc flc transcode *
	# FT:{START=--skip=%t}U:{END=--until=%v}D:{RESAMPLE=-r %d}
	[flac] -dcs $START$ $END$ -- $FILE$ | [sox] -q -t wav - -t flac $RESAMPLE$ - 

I'm able to play all files with part of previous convert.conf

flc flc transcode *
	# FT:{START=--skip=%t}U:{END=--until=%v}
	[flac] -dcs $START$ $END$ -- $FILE$ | [flac] -cs --totally-silent --compression-level-0 -