Dear Colleague,
Whether you sign the Offer letter or Appointment Letter both equally amounts to " agreed terms of appointment contract" You say there is a clause on non-compete clause for 1 year. The clause is biding. However there are legally different views by courts and says that such clause is not valid etc. Such clause is not at a healthy in the present scenario where every one is a competitor for ever one. Hence such clauses are no more valid and this clause is no way going to help the employer other than giving a moral threat to the employees. This is my view. Others may have different view on this too which we can not stop it. Overall such clause is against fundamental rights of a person.
However if the employer is intended to take you into task he may raise litigation against you and irrespective of final outcome you need to respond and undergo the process. This has to be looked more from " moral" aspect rather than "legal"
In this case a smooth discussion is also possible where in some of my previous organizations we allowed the talents to join employees with competitors despite such clause in appointment order based on the written commitment given by the said employees stating that they will not disclose any trade secret or other to the other company and will not share any data of the company at any cause etc. It gone well. In todays Tech world getting other company data is not much difficult and such clauses in the appointment contracts to be reviewed unless such clause is highly impacting the Trade/ Safety/ Secrecy of business etc.
Coming Back:
Legally such clauses are not enforceable. However-
Having singed a clause and breaching it - whether it is according to your conscience.
Are you prepared to under go the legal process if all it is raised by the employer for litigation ( may or may not it depends on employer's maturity level) - are few of the factors to be weighed before you take a call.
In case of breech is there any clause on specific compensation to be done etc to be studied.
Take call overall with your own clarity in mind.