ISO 27001 Certificate Renewal

Since your previous certification has expired, you need to go through all the certification processes again (i.e., first a certification audit, followed by surveillance audits).

Compared to ISO 27001:2005, ISO 27001:2013 has significant differences only in Annex A (security controls), so you do not need to consider a full fresh implementation (i.e., documents related to main clauses from sections 4 to 10 will need only some adjustments). 

For further information, see:
- ISO 27001 implementation steps https://advisera.com/27001academy/knowledgebase/iso-27001-implementation-checklist/
- How to make a transition from ISO 27001:2005 revision to 2013 revision https://advisera.com/27001academy/knowledgebase/how-to-make-a-transition-from-iso-27001-2005-revision-to-2013-revision/