how dangerous would it be to switch to 5.1-current?

[C. Kukulies]

With a gateway machine that runs 4.8 stable I'm considering to
switch to 5.1-current (cvsup) at the danger of being off-net 
after the upgrade. Should I?

 ifpi0: <AVM Fritz!Card PCI> port 0xd400-0
xd41f mem 0xef001000-0xef00101f irq 10 at device 9.0 on pci0
Oct 23 19:07:32 isdn-kukulies /kernel: ifpi0: ISAC 2085 Version A1/A2 or 2086/21
86 Version 1.1 (IOM-2) 

is my hardware.

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Chris Christoph P. U. Kukulies kuku_at_physik.rwth-aachen.de