Oracle Enterprise Manager Cloud Control Upgrade Guide describes how you can upgrade the following to Enterprise Manager Cloud Control 13c Release 2:
Enterprise Manager Cloud Control 13c Release 1(13.1.0.0)
Enterprise Manager Cloud Control 12c Release 5 (12.1.0.5)
Enterprise Manager Cloud Control 12c Release 4 (12.1.0.4)
Note:
If you have configured Oracle BI Publisher with 12c Release 3 (12.1.0.3), then you cannot directly upgrade to 13c. You must first upgrade to 12c Release 4 (12.1.0.4), 12c Release 5 (12.1.0.5), or 13c Release 1, and then upgrade to 13c Release 2.
If you have 12c Release 1 (12.1.0.1), 12c Release 2 (12.1.0.2), or 12c Release 3 (12.1.0.3), then first upgrade it to either 12c Release 4 (12.1.0.4), 12c Release 5 (12.1.0.5), or 13c Release 1 and then upgrade it to 13c Release 2.