I use the desktop version (download) of TurboTax Home & Business. Try forcing a download/software update if you are using the desktop version.
My case is actually for my father, who legally contributed $27.5k to his 403(b) plan at a private college (Duke University) in 2018. This amount was $18.5k + $6k (over 50) + $3k (his last year of the 15-year catch-up plan).
TurboTax worked for e-file for my father today on the desktop version, including his extra $3k (the 15-year catch-up, total limit of $27.5k after the age-50 $6k addition).
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I hope this helps! And I suggest that you bug Intuit customer service (by phone) about the needed parallel update to the online version.
