https://forums.garmin.com/developer/fit-sdk/A place to ask and answer questions related to the Flexible and Interoperable Data Transfer (FIT) Protocol.en-USTelligent Community 13https://forums.garmin.com/developer/fit-sdk/f/discussion/432872/discrepancies-between-fit-files-from-garmin-connect-and-api-api-downgraded/2071674Wed, 14 Oct 2026 22:54:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:6c71444c-66b3-413b-b5e3-2ebb6d14f679GregRFCount me as another user annoyed that Garmin is striping useful data out of the files.https://forums.garmin.com/developer/fit-sdk/f/discussion/443113/activity-profile-editor-for-edge-devices/2071618Wed, 14 Oct 2026 19:04:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:fbb66635-cf9a-488e-b1dc-4adfe95383b6dscurtisThe README got an update along with a few data fields that had "collisions". The main think was describing the difference between the Connected (mass storage) mode and the Offline mode for Edge devices that use MTP. Here's a section of the README file with the relevant info: Which Edge models this works with — and the two ways to use it There are two workflows , and which one you get depends on how your Edge connects to a computer. Both end with an edited profile on the device; they differ in who moves the file. Connected mode Offline mode Your Edge appears as a normal disk — a volume under /Volumes on macOS, a drive letter on Windows a "Portable Device" (MTP), or nothing browsable on macOS Models Edge 530 (tested) , and other USB Mass Storage Edges Edge 840 (tested) ; 540, 1040, 1050 reported as MTP The toolkit finds the device itself asks you for a folder of .fit profiles Writing the result Deploy — straight to the device Export — to a folder, then you copy it across Restore from backup yes no, it is a device operation — the panel points you at your backup folder instead Garmin moved the newer models to MTP (Media Transfer Protocol), which presents a firmware-controlled view rather than a real disk. Note this may have arrived on your device through a firmware update rather than being true when you bought it. Offline mode is not only for MTP devices — it is also how you edit a profile you pulled last week with nothing plugged in. Connected mode, step by step Plug the Edge in and wait for it to mount. Start the toolkit; it finds the device and lists your profiles. Edit screens, fields and layouts. Deploy. The toolkit backs up the original first, writes, then reads the file back and byte-compares before reporting success. Eject and restart the Edge. Offline mode, step by step Copy the profiles off the device with an MTP browser — Start the toolkit and choose "Work Without a Device…" , then point it at that folder. Edit exactly as you would with a device attached — the profile list, screens view, editor, backups, Clone and the boot-message editor all work the same. Export. It writes to a folder you choose, reads the result back and byte-compares it, and checks the file's own CRC before writing anything at all. Copy the exported file into Garmin/NewFiles/ on the device and restart the Edge. The filename matters, and the dialog handles it for you. The Edge matches profiles by filename on import and silently ignores anything that does not match — no error, no indication, the profile simply does not change. The save dialog pre-fills the original filename. Change it anyway and you get a warning naming the consequence, not a refusal: exporting a spare copy under another name is legitimate. startup.txt , the custom boot message, works in both modes. Does the NewFiles/ route actually work over MTP? Yes — confirmed repeatedly on an Edge 840. An edited ROAD profile has gone through it end to end, including a Connect IQ field that survived three chained edits, and a screen using a layout variant the 530 does not offer, which the 840 rendered correctly. A hand-built Totals.fit written the same way was also accepted. This was an open question until v1.5.0 and is recorded here because earlier versions of this README asked readers to help answer it.https://forums.garmin.com/developer/fit-sdk/f/discussion/432872/discrepancies-between-fit-files-from-garmin-connect-and-api-api-downgraded/2071456Wed, 14 Oct 2026 10:54:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:1a20ccd3-581a-4821-bfe2-c5bc395b875e1683866This is really annoying. I found Garmin's VO2 Max indicator to 1 or 2 decimal places to be a relatively reliable indicator of fitness vs. other competitor versions. Now I can't see this at this level of granularity. Really reduces the value of garmin products over other competitor products.https://forums.garmin.com/developer/fit-sdk/f/discussion/432872/discrepancies-between-fit-files-from-garmin-connect-and-api-api-downgraded/2071424Wed, 14 Oct 2026 06:34:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:60cf03d2-04b4-427a-bdd1-6cd18ab95677OcyeHi Garmin, I've been a Garmin user for >20 years and use third-party apps to analyze my training. Since recently, the FIT files shared with these apps no longer include metrics like VO2max, recovery time, training benefit, or lactate threshold, even though the original files still contain them. Please keep sharing my complete activity data with the apps I choose. It's my data. Thank you!https://forums.garmin.com/developer/fit-sdk/f/discussion/432872/discrepancies-between-fit-files-from-garmin-connect-and-api-api-downgraded/2071401Wed, 14 Oct 2026 00:14:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:e5b77635-49da-4076-b7e8-55817917ab77041c4e2a59e841a2b8da70688e323988What the *** Garmin? This is not a good look and will reconsider staying in your ecosystem if you keep trying to thwart access to my own data.https://forums.garmin.com/developer/fit-sdk/f/discussion/445980/csv-to-fit-with-python/2070974Mon, 12 Oct 2026 15:15:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:c773ed49-4638-47de-869d-9e1a351eab36muktihariI have no Python solution, but if your concern regarding Java is the heavy JVM machinery, my Go program can be an alternative since it’s a single binary program: https://github.com/muktihari/fit/tree/master/cmd/fitconv That said, I hope somebody else could come up with Python solution for you.https://forums.garmin.com/developer/fit-sdk/f/discussion/445980/csv-to-fit-with-pythonMon, 12 Oct 2026 12:38:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:0c748ab0-2992-413d-af08-45134af4c98cNiv-ParsonsI have some CSV data that is NOT compatible with the "FitCSVTool.jar" conversion program. I wrote a Python file to convert my source CSV in a compatible CSV file and all works just fine now. BUT, I have to use the Java tool to do this: java -jar C:\..\..\..\FIT_SDK\java\FitCSVTool.jar -c C:\PYTHON\KHP\FIT_File_Conversion\INPUTcsv C:\..\OUTPUT_%date:~-4,4%%date:~-7,2%%date:~-10,2%.fit This also works fine and the OUTPUT.fit file (with date appended etc) imports into Garmin Connect OK. Is there a way to NOT use JAVA for this conversion step but use PYTHON instead, so my conversion routine from incompatible CSV to compatible FIT is all done in Pythonhttps://forums.garmin.com/developer/fit-sdk/f/discussion/432872/discrepancies-between-fit-files-from-garmin-connect-and-api-api-downgraded/2070425Fri, 09 Oct 2026 15:14:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:c01c4210-056a-4a5d-8efa-abbfa444116a4040965It seems that there are even more restrictions on the way.https://forums.garmin.com/developer/fit-sdk/f/discussion/443113/activity-profile-editor-for-edge-devices/2070245Thu, 08 Oct 2026 23:06:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:79fe0278-8ca7-4dc0-8bda-65de7f8dd1f6dscurtisI just released version 1.6.0, it supports offline mode and is now aware of not just the Edge 530 but also the Edge 840 and all of the user screen layouts and special screen configurations in the Activity Profiles. It's also aware of the additional data field types that are supported on the Edge 840. For editing Activity Profiles or the startup.txt file from an Edge 840 (on the Mac) I used the OpenMTP program to pull and push the edited files.https://forums.garmin.com/developer/fit-sdk/f/discussion/432872/discrepancies-between-fit-files-from-garmin-connect-and-api-api-downgraded/2070208Thu, 08 Oct 2026 21:05:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:4a866961-fbd8-4002-ba95-e284d61a7bb12613403Garmin why? There is no reason for that discrepancies!https://forums.garmin.com/developer/fit-sdk/f/discussion/432872/discrepancies-between-fit-files-from-garmin-connect-and-api-api-downgraded/2070159Thu, 08 Oct 2026 19:03:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:2cbe64a2-cb15-407d-9fc4-24ea791a15eejohnpaneYes, for me too. Garmin, this really degrades my impression of your company!https://forums.garmin.com/developer/fit-sdk/f/discussion/432872/discrepancies-between-fit-files-from-garmin-connect-and-api-api-downgraded/2069583Wed, 07 Oct 2026 09:28:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:81b2a4d1-24b3-411c-bb78-d443aff07d97tgeoThis is happening againhttps://forums.garmin.com/developer/fit-sdk/f/discussion/389942/looking-for-corrupt-fit-files/2069530Wed, 07 Oct 2026 02:51:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:30a9262a-16bc-47c7-b8a1-5f8bc14f2ebdAlanIt seems some of your data does not follow the Garmin FIT file spec. I use the full version of DataNumen FIT Repair to fix it automatically. I think the data are fixed. See forums.garmin.com/.../2026_2D00_10_2D00_03_2D00_13_2D00_00_2D00_08_5F00_fixed.zip Before the fix: After the fix:https://forums.garmin.com/developer/fit-sdk/b/news-announcements/posts/fit-sdk-21-218-00-releaseTue, 06 Oct 2026 22:13:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:e177f18a-e89f-4727-a4b2-c53f8b1893e2Ben FITVersion 21.218.00 of the FIT SDK is available for download at Get the SDK | FIT SDK | Garmin Developers In this release: Python SDK Re-Added LICENSE.txt to GitHub repository Fix for encoding identical messages with different field order, which would cause file corruption JavaScript SDK Encoder now throws errors when trying to encode a field value that is not a number, string, boolean, or date. Fix for Typescript declarations so they now resolve under Node's module resolution Fix for encoding identical messages with different field order, which would cause file corruption Swift SDK Add typealiasing to FIT Types Unpin version of swift-collections from 1.2.0 C# SDK CheckIntegrity to return false when file is empty Java SDK Fix DateTime.fromInstant() constructor Profile Updates New Garmin Product Ids enduro4 approach_s72_43mm approach_s72_47mm New Manufacturer Ids exposure_lights forto_cycling Updated summary messages and fields In version 21.216 common fields were normalized across all of the summary messages: s e ssion, lap, split, split_summary, length, and segment_lap. The majority of the additions are in the split and split_summary messages. If a common field was available in one message is was made available in all the summary messages. session — 12 fields fields: avg_grade_adjusted_speed, avg_paddlesport_cadence, avg_push_cadence, avg_strokes_per_length, avg_swimming_cadence, avg_swolf, front_gear_shift_count, max_paddlesport_cadence, max_push_cadence, max_swimming_cadence, num_segment_laps, rear_gear_shift_count lap — 17 fields fields: avg_grade_adjusted_speed, avg_paddlesport_cadence, avg_push_cadence, avg_strokes_per_length, avg_swimming_cadence, avg_swolf, front_gear_shift_count, max_paddlesport_cadence, max_push_cadence, max_swimming_cadence, metabolic_calories, nec_lat, nec_long, rear_gear_shift_count, swc_lat, swc_long, total_pushes length — metabolic_calories segment_lap — metabolic_calories split — 107 fields, covering: All cadence, power, heart-rate, temperature, swimming, running, and stance metrics apnea_discipline, dive_section_type, first_lap_index, jump_count, left_right_balance Climbing fields: climb_grading_scale, climb_send, and all climb_grade_* fields Location and surface fields: nec_lat, nec_long, swc_lat, swc_long, surface_interval Split status and activity totals, including num_falls, num_laps, total_cycles, total_pushes, total_reps, total_strides, and total_strokes split_summary — 81 fields, covering: Average, maximum, minimum, cadence, power, swimming, temperature, stance, and stroke metrics climb_grading_scale and all climb_max_grade_* fields left_right_balance, max_distance, max_total_timer_time metabolic_calories, min_heart_rate, normalized_power Climb counters: num_climbs_attempted, num_climbs_completed, num_falls start_time, sport, sub_sport, swim_stroke, timestamps, and activity totals Additional updated messages and fields battery - timestamp and capacity barometer_data — enhanced_altitudehttps://forums.garmin.com/developer/fit-sdk/f/discussion/445331/js-sdk-decoder-crash-in-setaccumulatedfield-when-a-component-field-precedes-its-accumulated-target-field/2069416Tue, 06 Oct 2026 18:53:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:82af0a32-5b58-4559-9807-a7f1d0c59dd4ravelNot sure anymore. If I remember it correctly I downloaded the file from a Garmin website. I think it was an example fit file to show the differences between summary first and summary lasthttps://forums.garmin.com/developer/fit-sdk/f/discussion/444928/add-license-txt-file-to-garmin-fit-python-sdk/2069380Tue, 06 Oct 2026 17:34:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:42853581-7bc7-40cb-bed0-ec19886e7fd6Eli FITThank you for letting us know. We use the same license between all the SDKs and have updated the Python FIT SDK repository to include the License.txt github.com/.../fit-python-sdkhttps://forums.garmin.com/developer/fit-sdk/f/discussion/445331/js-sdk-decoder-crash-in-setaccumulatedfield-when-a-component-field-precedes-its-accumulated-target-field/2069379Tue, 06 Oct 2026 17:31:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:ea5b3732-961f-4ca4-b3b4-16722e756e90Grace FITThank you. Was the file exported directly out of Garmin Connect or have you decoded and re-encoded the file?https://forums.garmin.com/developer/fit-sdk/f/discussion/444478/bug-report-for-https-github-com-garmin-fit-python-sdk/2069378Tue, 06 Oct 2026 17:31:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:0b98a3b8-03e1-45f0-a573-a02be4070089Eli FITThis is now released as of 21.218. Give it a try and let us know if it works for you. https://github.com/garmin/fit-python-sdk/releases/tag/21.218.0 https://pypi.org/project/garmin-fit-sdk/https://forums.garmin.com/developer/fit-sdk/f/discussion/445331/js-sdk-decoder-crash-in-setaccumulatedfield-when-a-component-field-precedes-its-accumulated-target-field/2069206Tue, 06 Oct 2026 04:56:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:7ed38b18-82ca-4ce1-9c19-cbd722920aa6ravelHere is the link to the "triathlon_summary_first.fit" file: www.dropbox.com/.../triathlon_summary_first.fithttps://forums.garmin.com/developer/fit-sdk/f/discussion/445331/js-sdk-decoder-crash-in-setaccumulatedfield-when-a-component-field-precedes-its-accumulated-target-field/2069018Mon, 05 Oct 2026 15:42:00 GMTa9571b57-dd57-479e-8763-8f8a603e40aa:c3faedec-9e6a-4740-8dd5-07cdb1ef6435Grace FITWould you mind attaching the Forerunner 255 triathlon file you were seeing JS crash on?