Avoid serialization when entering date values in variables
If you enter the value "9999-12-31T23:59:59Z" Octopus will automatically convert it to "12/31/9999 11:59:59 PM".
Perhaps there could be a way to handle this more gracefully for users that need the value exactly as they put it?
The format filter variable substitution syntax (http://docs.octopusdeploy.com/display/OD/Variable+Substitution+Syntax#VariableSubstitutionSyntax-Filters) introduced in Octopus Deploy 3.5.0 now allows users to format the output of their variables in whichever means they want.
With this ability, the serialization format should be less of an issue.