Hi, and welcome to the October edition of this newsletter!
Two things from my end that are new from October…
First, I went live with the new version of my personal website - danclarke.com. This replaced my old, perhaps over-engineered, website/blog - with a shiny new static site built with 11ty. I moved the blog post listing away from the main homepage, as I want the main focus of that landing page to be a place I can direct people to for all my links (socials, and things like the podcast, YouTube, this newsletter, etc). I’m really pleased with it, and I think it’ll encourage me to start blogging again too!
The second thing was that I was honoured to have been invited onto the Azure & DevOps Podcast, hosted by Jeffrey Palermo! We chatted about personal productivity for developers, and it’s due to be published near the end of November. Jeffrey will also be joining me on my podcast in a few weeks too.
And with that, let’s move on to the newsletter and news items! As always, feel free to reply to this email to get in touch. Or ping me on any of the socials, which can be found on my above-mentioned new site, danclarke.com.
If you get value from this newsletter, please help me out by sharing it on your socials and with your tech friends and colleagues - it really helps me spread the word and keep the newsletter going 🙏 (at-mention me, and I’ll repost).
📰 News items and dev picks
Dotnet news
Understanding the worst .NET vulnerability ever: request smuggling and CVE-2025-55315 (by Andrew Lock) - Also a video by Ed Andersen about it here.
.NET 10 Release Candidate 2 - Not long to go until the main release!
.NET Conf agenda now live - the .NET Conf will be from November 11th to the 13th, and the agenda has now been published.
.NET Foundation election results - A massive congratulations to Irina Dominte and Jonathan Tower (both fellow Dometrain authors!) 👏
Announcing Sponsorship on NuGet.org - NuGet authors can now add a sponsor link to one of the approved sponsorship platforms (eg. GitHub Sponsors, Patreon, and a few more).
.NET Aspire is rebranding to just “Aspire” - I guess I should re-title the course then!
Wolverine 5.0 is Here! - Wolverine is a framework to add mediator-style and asynchronous/distributed messaging to dotnet applications - and they’ve just released a new major version.
Aspire MCP Server support coming soon! - This is pretty cool! A minimal, in-process MCP Server to query your AppHost resources!
Announcing a new OData.NET serializer - A new high-performance OData serializer that's up to 5 times faster and far more memory-efficient.
AI news
Semantic Kernel and Microsoft Agent Framework - “Microsoft Agent Framework is the successor to Semantic Kernel for building AI agents”
GitHub Spec Kit - Definitely high on my list of things to play with and learn! The project is here, and there’s a blog post here. Also, a recent episode of .NET Rocks about it here.
ChatGPT Atlas - OpenAI release its own browser! Currently only available on Mac.
Playwright Agents - This is amazing! That link is a short video - definitely worth a watch!
Apps in ChatGPT and the new Apps SDK - One of the OpenAI Dev Day announcements. Chat with apps inline as part of the ChatGPT UI! And also build your own with the Apps SDK.
OpenAI AgentKit - Another OpenAI Dev Day announcement. This allows you to create workflows on a visual canvas to build and deploy AI agents.
Introducing Claude Haiku 4.5 - A new Anthropic focused on speed and cost.
Introducing Agent Skills (Anthropic) - Also a blog post by Simon Willison here.
Others
GitHub Universe 2025 - The conference has now finished, but its keynote and some videos are available to watch. There’s also a video going through the biggest announcements.
Introducing Agent HQ (GitHub Universe announcement)
AWS outage - This was pretty huge and took down a lot of things! On the plus side, it meant less meetings that day, as it also took Zoom down! And yes, it was DNS.
Azure outage - And not to be outdone, a week later, Azure also had an outage - which was traced to Azure Front Door config. For me, whilst it didn’t affect Zoom meetings like the AWS one did - it did take down the ability for customers to sign in (Azure B2C) to the sites of a client of mine! 🫣
Dev Comic pick of the month
Perfect timing for Halloween, which at the time of writing, we did last night with our kids. Thankfully, it didn’t involve data loss, though! 😄
(source)
Dev Tip - Dumpify
This month’s dev tip is a Nuget package called Dumpify. If you’re a fan of LINQPad, then you’ll love this! It adds a LINQPad-style “Dump()” extension method to all objects to allow you to dump them out in console applications in a structured and colourful way.
Sponsorship opportunities
I’m looking for sponsors for both the podcast and this newsletter. Details of podcast sponsorship can be found here. Feel free to reply to this email to discuss further.
The Podcast 🎙
Yikes - writing this has made me realise that I didn’t record a single episode in October! 🙈 I’ll definitely have to make that up in November!
I did publish an episode that was recorded in September, though…
This was with Olorunfemi Davis, and we chatted about AI, Microsoft's various Copilots (including Copilot Studio), Semantic Kernel, and more!
I’m also mid-way through editing the next episode, which was with Jan De Dobbeleer, the creator of Oh My Posh, which is what we geeked out on! I’ll get this finished and published asap.
Also, just a reminder that we have a Discord community for the podcast! It would be great to see you there :)
Podcast Discord community
.NET Oxford (user-group)
In October, we also had our quarterly .NET Oxford meetup, and for this one, we attempted an “Unconference” format. So rather than our usual talk-based format, instead we all submitted topics we wanted to chat about, then voted on them, and then we started the group discussions. The submission and voting was done at the event using Slido. Sadly, it wasn’t a huge turnout (smaller than we usually have), but actually that worked out really well, and we had some great discussions! Here’s what we spoke about…
We’re now planning the next meetup, which will be in December.
My Dometrain Courses
Below are details of my Dometrain courses. There’s also a bundle that includes both the Docker and Kubernetes courses, which can be found here.
Docker for Developers
This course will teach you everything you need to know about Docker and containers. From what containers and images are; to how to build your own; to security and networking; docker-compose; and much more!
Kubernetes for Developers
Once you understand Docker, containers, images, etc - it’s time to move onto the next level and learn a container orchestrator - and Kubernetes has clearly won the battle here! My Kubernetes course is rammed-packed full of demos (pretty much all the way through), which are easy to follow along with downloadable YAML files and scripts. We start with the basics, then later move on to more advanced topics like services meshes and operators.
JetBrains Rider
Rider is an amazing .NET IDE by JetBrains. This course is 6 hours of content - covering hotkeys, refactoring, navigation, debugging, git, testing, AI, profiling, remote collaboration, and much much more!
Aspire
Aspire is Microsoft's vision for how every .NET developer will develop systems. It is a cloud-ready stack for production-ready, distributed applications using .NET, and it makes it extremely easy to develop, run, and test your systems locally. With unmatched dev-time orchestration, integrations with third-party services, and excellent tooling, .NET Aspire aims to make working with the cloud and technologies like Docker and Kubernetes easier than ever.
If you’ve made it this far into the newsletter - I’m hoping that means you’ve
both enjoyed it and found it useful. If you can help me out and share with your developer friends at work and on social media, that would be amazing!
Again - feel totally free to reach out to me, and let me know your thoughts on the newsletter. And see you back in your inbox next month for the next edition! 👋
Bluesky (my primary place)
Twitter (using less nowadays)
LinkedIn
Discord
Mastodon (rarely used)
Threads (rarely used)
