Automatically notifying about SD-JSON lineup changes

Hello,

I'm using tv_grab_sd_json, with selected channels from the 
GBR-0001207-DEFAULT lineup (Oxford UK Freeview DVB-T transmissions). I 
first set this up a week ago, and among the channels I picked was one 
that the grabber called "Channel 5 Plus 24 (Free)" and which had ID 
97294. All was fine for a few dyas.

Yesterday I noticed that I had no more listings for Channel 5+24. I 
raised this with Schedules Direct. It turns out that they changed the 
lineup for GBR-0001207-DEFAULT removing "Channel 5 Plus 24 (Free)" ID 
97294 and adding "Channel 5 Plus 24" ID 56888.

(The difference is that the new channel has listings for 24 hours 
whereas the old had large blocks of "SIGN OFF". I thought that SD had 
made a mistake because as far as I was aware Channel 5+24 was not 24 
hours on Freeview (and indeed 
https://www.freeview.co.uk/why-freeview/channels/524 says it isn't 24 
hours) but I notice from direct observation that SD are indeed correct 
and that the official website is out of date!)

Anyway, Robert Kulagowski said to me:

  >If the lineup changes upstream, then your grabber should realize that
  >(there's a field that indicates when the lineup was updated) and then
  >let you know that, or change the lineup, or something.
  >
 
 >"metadata":{"lineup":"GBR-0001207-DEFAULT","modified":"2016-07-01T20:04:14Z","transport":"DVB-T"}}

So the question is, does tv_grab_sd_json "notice" these SD lineup 
changes based on the modified date, and if not, can it be made to do so? 
How would these be best communicated to downstream apps?

In my case I use mythfilldatabase to call tv_grab_sd_json. Would it be 
appropriate to modify the MythTV database automatically to reflect the 
lineup changes?

I realise this is a big problem, as in many case this would require 
retuning, although not in this particular case. But if nothing else, it 
would be good for the grabber (and mythfilldatabase) to inform the user 
about the lineup change, based on the modified date.

What do people think?

John

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