Please provide more info on which network standard you're referring to (or screenshots of where you saw this address). 5-octet IP addresses are not standard and will not be supported by most software that interacts with IPv4.

It may be a nonstandard version of port notation, but without more info (like where you encountered the address), there's not much anyone can do to help. Internal addresses typically would just reduce the CIDR value (or adjust the subnet mask) to retain more host addresses, so it's unlikely to be due to IPv4 exhaustion.