Cannot pay LN invoice for amounts less than 10k sats via BTCPay's unified QR code

[yanascz]

I'm unable to pay 3 857 sats via LN when I scan a unified QR code provided by BTCPay Server. Works fine using Breez.

iPhone 13, iOS 16.1.2, Phoenix 1.5.4

Example (already expired) QR code content:

bitcoin:bc1qm60ehg4fl3k7ldq5558pluvtqtmp9culch44t8?amount=0.00003857&LIGHTNING=LNBC38570N1P3ER83SPP5UTWMDA8ZJV6PKZNUAY3TG26VG4U3GG8Z375HFYN9KJNVX2Q6AU4QDRD2PSKJEPQW3HJQ5MPW3HHX6RFF3SKYUEQ9P8HYER9WGSYJ3P6YPCX7UEDV9C8QHEJVF99W52VG3MNGNN6G3GHQ7J20Y656MF3FFSNVMM9V3VJJCQZPGXQZUYSP5SQC77KJ40CG3QSZLNYT78MQLH605RCLMN2D4LDWHXWWJK5Z5GQ9S9QYYSSQ9KUF8ZFN2KG4662FL2ZPFK623TTSMC3LEQRH6LTVUX94ESJR4YHKQE6WCGKSCMF0VKEPHYJQ2CYGCUHA4FFWDSPJX2W4GWMG2K5XPXQPMYE6ZR

[dpad85]

@robbiehanson it seems the iOS app enforces the 10k sat minimum amount for on-chain payments even when the user decided to pay with Lightning.

As a workaround if you still need to pay that invoice, you can dismiss the 10k sat error message by changing the amount then put it back to its initial value of 3857 sat. The error will go away and you should be able to pay.

[yanascz]

As a workaround if you still need to pay that invoice, you can dismiss the 10k sat error message by changing the amount then put it back to its initial value of 3857 sat.

Confirmed, works fine as a workaround!

[robbiehanson]

Thanks for reporting this. The bug has been fixed, and the fix will be available in the next (major) app release: v1.6.0

[prusnak]

@robbiehanson Are you 100% sure Unified QR codes are correctly supported on Android (legacy) too?

[dpad85]

Are you 100% sure Unified QR codes are correctly supported on Android (legacy) too?

Yes the Android app supports QR codes that contain a bitcoin address with a lightning parameter, and will let the user choose how the payment is made.