4.0.0 is the first update since 3.2.0 (April 2026). It adds four major features and changes the default behavior of cloud sync.

■ Identification from a photograph (new)

Photographs taken with the camera or chosen from the library are classified on the device, with a similarity score at each rank from phylum down to species. Photographs are never uploaded and no connection is needed; the model is downloaded once on first use (about 140 MB). Where confidence extends only to genus, the result stops at genus rather than proposing a species name. Results are kept on the device and can be compared, shared as a card, or deleted.

■ Offline Rudy Map (new)

Downloaded once, the Taiwan topographic map — contours, hillshading and place-name index — works with no connection, with a new release each Thursday. A full edition (386 MB) and a light edition (194 MB) are both kept and can be switched between; smaller areas may be downloaded at high zoom. Also added: offline place-name search, coordinate entry (decimal degrees, degrees-minutes-seconds, TWD97 two-degree zone), a compass reading bearing and elevation, and three map styles.

■ Trail recording (new)

Recording starts with a single press and continues in the background, with progress shown on the Lock Screen throughout. GPX, KML and KMZ are supported for import and export; waypoints may be marked and photographed along the way, and an elevation profile and trip card follow on completion. A footprint layer records the trails you have walked and accumulates distance against Taiwan's trail network.

■ Backtracking and off-route alerts (new)

The route walked in is fixed as a reference line; straying about 50 m from it vibrates, and the app reports your distance from the line, the distance remaining to the trailhead, and — from your pace on the day — an estimated arrival time set against sunset. A separate alert appears when you are more than about 60 m from any known trail. Both work entirely offline.

There is no voice guidance, no turn-by-turn direction, and no shortcut will ever be proposed.

■ Summit records (new)

Named summits you walk over are recorded automatically, with no check-in required; Taiwan's Top 100 and Small Top 100 carry a badge. Nothing is pushed at you and no count of remaining summits is shown.

■ Measurement along the trail (new)

Two points placed on the map snap to the nearest trail; distance, ascent and descent follow that trail rather than the straight line between them. Where a section has another way round, both are drawn for comparison, and loop trails report the length of the full circuit.

■ Rainfall improvements

Rain probability moves from 22 counties to 368 townships; one-hour quantitative radar forecasts are added; the cumulative rainfall scale extends beyond 1,500 mm; and a long press on the map reads out rainfall and administrative district at that point.

■ Change to cloud sync (please note)

In 3.2.0 and earlier, spots and search history were synchronized to the cloud even when signed out. From this version they are synchronized only after signing in, and data previously held in the cloud under anonymous accounts has been deleted.

■ Other

Species, spots and trip cards can now be shared, and shared links open directly in the app. Spots accept a species name, notes and photographs, and are separated into mushroom spots and points of interest. Several layout problems at large text sizes have been corrected, and a link to the user guide at guide.nature-booklets.cc has been added to Settings.