The 12th certificate from Rural Institute of Open Schooling also known as RIOS is valid and can be used for jobs in LTD companies without any issue RIOS is affiliated with Chhattisgarh State Open School which is a government recognized board and it is approved by COBSE and MHRD that means the RIOS 12th certificate is treated equal to certificates from CBSE or any other state board if you passed in 2015 your certificate is still valid today because there is no expiry date for such certificates it remains valid for all kinds of jobs and higher studies LTD companies usually accept it during document verification just like other board certificates if any company refuses to accept it you can show them official documents from RIOS that prove its recognition and affiliation you can also talk to the HR or higher authority and explain that your certificate is government approved and legally valid RIOS certificates are accepted in UPSC banking state PSC private jobs and also in colleges for further education so your 2015 certificate is still useful and fully acceptable unless a company has some very specific policy which is very rare overall there is nothing to worry about your RIOS 12th certificate is legally valid and you can confidently use it for job applications