Tvheadend

After restart it seems tvheadend remembers the channel "XMLTV: Omrop Fryslân (Omrop Frysl__n)", but this is not always the case ?!

I also have a problem with no Polish character in EPG. Before update to version 3.9.1733 i have OK polish character.

Please, attach the EPG source file (in a .zip or other compressed format to not change the encoding)..

Encoding of the guide.xml file: XML 1.0 document, UTF-8 Unicode (with BOM) text

You should use an ascii name for the "id" attribute without spaces. The actual channel name is specified in the display-name subelement.

See also the xmltv DTD regarding the "channel" element:

[..]
Each channel has one id attribute, which must be unique and should
preferably be in the form suggested by RFC2838 (the 'broadcast'
element of the grammar in that RFC, in other words, a DNS-like name
but without any URI scheme).
[..]

So your file should look something like this (just make sure the id is specified according to RFC2838):

  <channel id="omrop.fryslan">
    <display-name lang="nl">Omrop Fryslân</display-name>
    <url>http://www.tvgids.nl</url>
  </channel>

I am also parsing chinese TV listings without issues, there an example channel entry would be:

<channel id="cctveurope">
 <display-name>CCTV-4 (欧洲)</display-name>
 <display-name>CCTV4</display-name>
</channel>