My MHCN says that the new advice suggests solids from 4 months is a good idea (at least for some babies, evidently).
The allergies and early commencement of solids are two different things. Last year a baby food company sponsored a MCHN education session where they were informed the WHO guidelines for commencement of solids was about to change. They aren't. Just a convenient *education* session to promote their product. Be dubious and check where their change of practice has come from.

As for the allergies, there is now some evidence to suggest the delay for introducing certain foods is probably of no value (except for honey due to botulism). So, for example, you could introduce eggs / nuts etc when you feel ready to rather than after a certain time frame with no difference in allergy rates. If you will be allergic, you will be allergic.

Ultimately, we all get conflicting advice on solids and it probably will change for every child you have Just do what suits your baby and what you feel comfortable with.