When running Thunderbird 60.7.0 outgoing messages would be received with questions marks inserted throughout current message and entire thread such as seen here as an example: "attached is funding proposal draft from back then.?? First section of "requirements"?? matches value intrinsically unique to language, I believe.??" Simultaneously TEXT ENCODING settings were in fixed default configuration; could not be changed from OUTGOING MAIL: Unicode (UTF-8 and INCOMING MAIL: Western (ISO-8859-1). Attempted changes in trying to fix this issue of outgoing inserted question marks would be selected, OKed, and Fonts & Encoding then Options closed and when immediately reopened the attempted changes would be reverted back to fixed default settings. So I uninstalled version 60.7.0 and reinstalled the prior Thunderbird release 60.6.0. That seemed to solve the issue in that it was possible to permanently configure both incoming and outgoing to Unicode (UTF-8) so that those settings held after closing the settings window and Thunderbird Options application suite. Sending a prior thread test message to myself from the account address involved indicated the issue was resolved; no question marks inserted. But today the same issue involving added question marks to outgoing messages and inability to change TEXT ENCODING settings from fixed default configuration as note above has returned. Uninstalling and reinstalling Thunderbird 60.6.0 was ineffective as a possible solution. So at present I'm running release 60.6.0, not able to change TEXT ENCODING setting, and faced with unresolved issue of Thunderbird inserting question marks throughout text portions of out going messages. Would you kindly advise ASAP me on how to resolve this issue? Thank you - hkjr