Create a release with specific version

# Load octopus.client assembly
Add-Type -Path "path\to\Octopus.Client.dll"

# Octopus variables
$octopusURL = "https://youroctourl"
$octopusAPIKey = "API-YOURAPIKEY"
$spaceName = "default"
$projectName = "MyProject"
$channelName = "default"
$releaseVersion = "1.0.0.0"

$endpoint = New-Object Octopus.Client.OctopusServerEndpoint $octopusURL, $octopusAPIKey
$repository = New-Object Octopus.Client.OctopusRepository $endpoint
$client = New-Object Octopus.Client.OctopusClient $endpoint

try
{
    # Get space+repo
    $space = $repository.Spaces.FindByName($spaceName)
    $repositoryForSpace = $client.ForSpace($space)

    # Get project
    $project = $repositoryForSpace.Projects.FindByName($projectName)

    # Get channel
    $channel = $repositoryForSpace.Channels.FindOne({param($c) $c.Name -eq $channelName -and $c.ProjectId -eq $project.Id})

    # Create a new release resource
    $release = New-Object Octopus.Client.Model.ReleaseResource
    $release.ChannelId = $channel.Id
    $release.ProjectId = $project.Id
    $release.Version = $releaseVersion
    $release.SelectedPackages = New-Object 'System.Collections.Generic.List[Octopus.Client.Model.SelectedPackage]'

    # Get deployment process
    $deploymentProcess = $repositoryForSpace.DeploymentProcesses.Get($project.DeploymentProcessId)

    # Get template
    $template = $repositoryForSpace.DeploymentProcesses.GetTemplate($deploymentProcess, $channel)

    # Loop through the deployment process packages and add to release payload
    $template.Packages | ForEach-Object {
        # Get feed 
        $feed = $repositoryForSpace.Feeds.Get($package.FeedId)
        $packageIds = @($package.PackageId)
        $version = ($repositoryForSpace.Feeds.GetVersions($feed,$packageIds) | Select-Object -First 1).Version
        $selectedPackage = New-Object Octopus.Client.Model.SelectedPackage
        $selectedPackage.ActionName = $_.ActionName
        $selectedPackage.PackageReferenceName = $_.PackageReferenceName
        $selectedPackage.Version = $version

        # Add to release
        $release.SelectedPackages.Add($selectedPackage)
    }

    # Create the release
    $releaseCreated = $repositoryForSpace.Releases.Create($release, $false)

    # Display created release
    $releaseCreated
}
catch
{
    Write-Host $_.Exception.Message
}

// If using .net Core, be sure to add the NuGet package of System.Security.Permissions
#r "path\to\Octopus.Client.dll"

using Octopus.Client;
using Octopus.Client.Model;

// Declare working varibles
var octopusURL = "https://youroctourl";
var octopusAPIKey = "API-APIKEY";
var spaceName = "default";
string projectName = "MyProject";
string channelName = "Default";
string releaseVersion = "1.0.0.3";

// Create repository object
var endpoint = new OctopusServerEndpoint(octopusURL, octopusAPIKey);
var repository = new OctopusRepository(endpoint);
var client = new OctopusClient(endpoint);

try
{
    // Get space+repo
    var space = repository.Spaces.FindByName(spaceName);
    var repositoryForSpace = client.ForSpace(space);

    // Get project
    var project = repositoryForSpace.Projects.FindByName(projectName);

    // Get channel
    var channel = repositoryForSpace.Channels.FindOne(r => r.ProjectId == project.Id && r.Name == channelName);

    // Create release object
    Octopus.Client.Model.ReleaseResource release = new ReleaseResource();
    release.ChannelId = channel.Id;
    release.ProjectId = project.Id;
    release.Version = releaseVersion;
    release.SelectedPackages = new List<Octopus.Client.Model.SelectedPackage>();

    // Get deployment process
    var deploymentProcess = repositoryForSpace.DeploymentProcesses.Get(project.DeploymentProcessId);

    // Get template
    var template = repositoryForSpace.DeploymentProcesses.GetTemplate(deploymentProcess, channel);

    // Loop through the deployment process packages and add to release payload
    foreach (var package in template.Packages)
    {
        // Get feed
        var feed = repositoryForSpace.Feeds.Get(package.FeedId);
        var packageVersion = repositoryForSpace.Feeds.GetVersions(feed, new[] { package.PackageId }).First().Version;

        // Create selected package object
        Octopus.Client.Model.SelectedPackage selectedPackage = new SelectedPackage();
        selectedPackage.ActionName = package.ActionName;
        selectedPackage.PackageReferenceName = package.PackageReferenceName;
        selectedPackage.Version = packageVersion;

        // Add to release
        release.SelectedPackages.Add(selectedPackage);
    }

    // Create release
    var releaseCreated = repositoryForSpace.Releases.Create(release, false);
    Console.WriteLine("Created release with version: {0}", releaseCreated.Version);
}
catch (Exception ex)
{
    Console.WriteLine(ex.Message);
    return;
}