David G3YYD announced 2Tone version 21.03a today. I asked him what changed relative to the 2Tone version 21.02a included with
WinWarbler, here is his response:

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The Writelog fix and minor changes to the source code - removing old code that is no longer used. I also added the N1MM
documentation that I had left out last time but had intended to add in to make it easier for guys who prefer pictures over words. I
trialled the picture system with some UK amateurs and they found it helpful. However there are words just not as many!

In terms of decode performance no difference.
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Thus I am not planning to include 2Tone 21.03a in a future version of WinWarbler. If anyone would like access to David's improved
N1MM documentation, it's included in the 21.03a zip archive available here:

https://www.rttycontesting.com/downloads/2tone/

73,

Dave, AA6YQ