Please note that most sofware projects (such as wxWidgets) provide its own way of updating catalogs (typically with makefiles), so it may be undesirable to do in poEdit.
This feature depends on settings in Catalog Settings dialog and is disabled unless you filled-in "Paths" panel.
When updating, poEdit will recursively search all specified paths, looking for known file types and scanning them for translatable strings. This process may take a while. When done, poEdit will display summary of new and obsolete strings (unless disabled in Preferences).
If enabled, poEdit will attempt roughly translate new entries according to its database of known translations. See Translation Memory section for details.