This Gist provides a suggested pattern for serializing / deserializing PowerShell v5 class instances

PowerShell v5 Class Serialization Pattern.ps1

class Person {
    [ValidateNotNullOrEmpty()]
    [string] $FirstName;
    [ValidateNotNullOrEmpty()]
    [string] $LastName;

    [string] $Address;

    Person([string] $First, [string] $Last) {
        $this.FirstName = $First;
        $this.LastName = $Last;
    }

    [string] Serialize() {
        return $this | ConvertTo-Json;
    }

    static [Person] Deserialize([string] $Json) {
        $Deserialized = ConvertFrom-Json -InputObject $Json;

        $Person = [Person]::new($Deserialized.FirstName, $Deserialized.LastName);
        $Person.Address = $Deserialized.Address;

        return $Person;
    }
}

### Instantiate the Person class
$Person = [Person]::new('Trevor', 'Sullivan');
$Person.Address = '111 First Street';

### Serialize the object instance
$JsonText = $Person.Serialize();

### Deserialize the object instance
$Person = [Person]::Deserialize($JsonText);