  The one-electron quantum-electrodynamic corrections to the magnetic-dipole
transition amplitude between the fine-structure levels (1s^2 2s^2 2p) ^2P_3/2 -
^2P_1/2 in boronlike ions are calculated to all orders in (\alpha Z). The
results obtained serve for improving the theoretical accuracy of the lifetime
of the (1s^2 2s^2 2p) ^2P_3/2 level in boronlike argon.
