Austria still has compulsory military service (Wehrdienst) or alternative civilian service (Zivildienst) for all male citizens deemed fit for call-up (tauglich) up to the age of 35. So you would be required to complete military or alternative military service were you naturalise before the age of 35. In some circumstances you may be exempted from military service if you have already done it in the country you previously held citizenship of (Britain has no national service, so this would not apply).
In order to do alternative civilian service instead of military service you have to specifically submit a declaration in advance that you wish to not do military service for conscientious objection reasons.
Was this content useful?
Let us know if you found the content useful, even if the answer wasn't what you'd hoped for. That’s the only way we can improve.