If you installed the beta over the top of the release version (choice 2 above), then your process will be more complicated. Please consult this <a href="https://support.mozilla.org/kb/thunderbird-beta">beta support article.</a>
Os ydych wedi gosod y beta dros ben y fersiwn rhyddhau (dewis 2 uchod), yna bydd eich proses yn fwy cymhleth. Darllenwch <a href="https://support.mozilla.org/kb/thunderbird-beta">erthygl cefnogi y beta.</a>