[drupal-support] Textile not applied after upgrade

I am upgrading a 4.5.2 site to 4.6. After upgrading, nodes that were textiled are no longer textiled. The edit tab shows that they are of input format "Textile". That input format applies just a single filter: Textile, and without tags. This has happened to me before during earlier upgrades. Eventually (after continuing work adding contrib modules), Textile was again applied to nodes, but I never understood why it stopped being applied, nor why it resumed being applied. Can anyone enlighten me? Thanks, Cheryl