Is internal auditor of ISO 9001:2008 allowed to conduct internal audits in accordance with ISO9001:2015?

Each organization has the authority to determine its competency requirements for its internal auditors. Normally, organizations consider that internal auditors should have knowledge of the audit criteria (ISO 9001:2015 in this case) and should have training in internal audits. You can even decide that an auditor has to study a book on audits or attend an online course and do an in-house exam. Internal auditor competence requirements can be established in a job description, for example. IAF and other rules are applicable to certification auditors. So, the only criteria is: does the internal auditor complies with the internal auditor competency requirements?

The following material will provide you information about internal auditors:

• ISO 9001 – ISO 9001 internal auditor training: Is it for me? - https://advisera.com/9001academy/blog/2015/06/02/iso-9001-internal-auditor-training-is-it-for-me/
• Free online training ISO 9001:2015 Internal Auditor Course – https://advisera.com/training/iso-9001-internal-auditor-course/
• Book -  ISO Internal Audit: A Plain English Guide - https://advisera.com/books/iso-internal-audit-plain-english-guide/