As I said, the encoder and decoder settings are being stored differently now. I haven't fully tested 2.1.8 using an old settings file to see if settings.txt is properly updated.
older
=</CUEConfigAdvanced>
ExternalEncoder0Name=cuetools
ExternalEncoder0Extension=wav
ExternalEncoder0Lossless=1
ExternalEncoder0Settings=<WAVWriterSettings />
ExternalEncoder1Name=cuetools
ExternalEncoder1Extension=m4a
ExternalEncoder1Lossless=1
ExternalEncoder1Settings=<ALACWriterSettings>
= <EncoderMode>5</EncoderMode>
=</ALACWriterSettings>
ExternalEncoder2Name=FLACCL
ExternalEncoder2Extension=flac
ExternalEncoder2Lossless=1
ExternalEncoder2Settings=<FLACCLWriterSettings>
= <EncoderMode>8</EncoderMode>
= <GPUOnly>false</GPUOnly>
= <DeviceType>CPU</DeviceType>
=</FLACCLWriterSettings>
ExternalEncoder3Name=cuetools
ExternalEncoder3Extension=flac
ExternalEncoder3Lossless=1
ExternalEncoder3Settings=<FlakeWriterSettings>
= <EncoderMode>5</EncoderMode>
=</FlakeWriterSettings>
2.1.8
Advanced={
= "encoders": [
= {
= "$type": "CUETools.Codecs.WAV.EncoderSettings, CUETools.Codecs"
= },
= {
= "$type": "CUETools.Codecs.ALAC.EncoderSettings, CUETools.Codecs.ALAC",
= "EncoderMode": "5"
= },
= {
= "$type": "CUETools.Codecs.FLACCL.EncoderSettings, CUETools.Codecs.FLACCL",
= "EncoderMode": "8"
= },
= {
= "$type": "CUETools.Codecs.Flake.EncoderSettings, CUETools.Codecs.Flake",
= "EncoderMode": "5"
= },
[...]
see also https://hydrogenaud.io/index.php?topic=116743.0