Prior to Release 9.1, if you configured two IP addresses when you defined the DHCP Server vendor options, only one IP address was included in Option 43. The workaround was to include two backslashes (\\) in the configuration.
For example:
ip dhcp-server vendor-option-data 1 value 192.0.2.2\\,192.0.2.5
This workaround is no longer required in Release 9.1. You must remove the backslashes (\\) in the configuration before you upgrade to Release 9.1 or later.