Mattias Karlsson
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devlead.se
Mattias Karlsson
@devlead.se
2.5K followers 610 following 2.3K posts
Partner & Technical fellow at WCOM AB
.NET Microsoft MVP.
Been coding since the ’80s (C128 & Amiga).
Father of 2, husband of 1.
Occasionally blogs at https://devlead.se
Posts Replies Media Videos
devlead.se
That wonderful feeling when you meet a deadline with room to spare, having been repeatedly asked for updates throughout the whole process, only to be met with total silence after you deliver.🤣😢😎
September 17, 2026 at 12:30 PM
Reposted by Mattias Karlsson
gaprogman.com
This 👇
blowdart.me Barry Dorrans @blowdart.me · 20h
Reminder ⏰

.NET 8 and .NET 9 support ends on November 10th.

Get your apps moved to .NET 10 before then.
September 16, 2026 at 9:43 PM
Reposted by Mattias Karlsson
blowdart.me
Reminder ⏰

.NET 8 and .NET 9 support ends on November 10th.

Get your apps moved to .NET 10 before then.
September 16, 2026 at 5:25 PM
Reposted by Mattias Karlsson
dotnetfoundation.org
Cake v6.3.0 is out 🚀🍰 NuGetLogin for GitHub Actions OIDC trusted publishing (no long-lived API keys), nullability-aware aliases, typed dotnet tool aliases, verbosity via config, and light-theme-friendly reports.
hubs.li/Q04xvj2B0 #dotnet #devops #csharp
September 16, 2026 at 8:38 PM
Reposted by Mattias Karlsson
khalidabuhakmeh.mastodon.social.ap.brid.gy
Anyone consider themselves a #blazor Consultant and would like to try out an experiment with me? Looking for a handful of professionals who like working with the technology.

#dotnet
September 16, 2026 at 7:49 PM
Reposted by Mattias Karlsson
cakebuild.net
Cake v6.3.0 is out 🚀🍰

NuGetLogin for GitHub Actions OIDC trusted publishing (no long-lived API keys), nullability-aware aliases, typed dotnet tool aliases, verbosity via config, and light-theme-friendly reports.

cakebuild.net/blog/2026/09...

#dotnet #devops #csharp
Cake - Cake v6.3.0 released
cakebuild.net
September 14, 2026 at 8:44 PM
devlead.se
One of my favorite .NET conferences, Swetugg, just opened its CFP for 2027! See you there?

sessionize.com/swetugg-stoc...

#dotnet #cfp
Swetugg Stockholm 2027: Call for Speakers
Our vision is to create a good quality .NET conference with relevant content that is also affordable. We include everything from the shiny new things ...
sessionize.com
September 14, 2026 at 7:53 PM
Reposted by Mattias Karlsson
cakebuild.net
We are starting to prepare our next release, 6.3.0 ( github.com/cake-build/c... ). This is your friendly reminder that if you haven't pinned to a specific version of Cake, you should do it now :-) 📌 🍰 cakebuild.net/docs/writing...
cake-build/cake
:cake: Cake (C# Make) is a cross platform build automation system. - cake-build/cake
github.com
September 14, 2026 at 6:07 PM
devlead.se
Just about to cast my vote early in the Swedish elections! Even with a queue today, I love it. It’s a privilege to live in a country that lowers the bar to vote and where democratic outcomes are always respected, even if it's not the result you personally hoped for.
September 12, 2026 at 11:46 AM
Reposted by Mattias Karlsson
roleo.eurosky.social
The number of cases of cervical cancer reported in Scotland among women given the HPV vaccine at 12-13 years of age is now zero.

Zero. Zero. Zero. Zero. Zero. Zero. Zero. Zero. Zero. Zero. Zero. Zero. Zero. Zero. Zero. Zero. Zero. Zero. Zero. Zero. Zero. Zero.

Zero.

www.bbc.com/news/article...
No cervical cancer cases in fully HPV-vaccinated women in Scotland
A study published by Public Health Scotland finds that the HPV vaccine is "highly effective".
www.bbc.com
September 8, 2026 at 6:50 PM
Reposted by Mattias Karlsson
whataweekhuh.bsky.social
Captain Haddock looking very frazzled, saying, “What a week, huh?” Tintin leans into the frame and says, “Captain, it’s Wednesday.” Snowy aka Milou is very excited about the drink he has found. Viñeta de Tintin El capitán Haddock, sentado a una mesa y con aspecto de estar agotado, dice: "¡Menuda semana, ¿eh?". Tintín, a su derecha, le dice: "Capitán, es miércoles". A la izquierda, Milú mira muy contento la bebida que está en la mesa.
September 9, 2026 at 10:27 AM
devlead.se
When you maintain more than 50 #dotnet OSS projects, an SDK/Servurity update can lead to a long tail of releases, so to reduce the number of releases and ensure the latest bits possible in each release, I've resorted to going in waves based on the dependency graph, automation is nice here.
Generated checklist, issue in private repo, waves of dependencies, when verified on NuGet, the next wave gets updated and released, and so on.
September 9, 2026 at 7:45 AM
Reposted by Mattias Karlsson
devlead.se
.NET 11 RC 1 was just released🎉, and it's got a go-live license; let's ship some prod workloads, analyze, and learn for the RTM release in November🚀#dotnet

dotnet.microsoft.com/en-us/downlo...
Go-live releases are supported by Microsoft in production. These are typically our release candidate builds, just before the generally available (GA) release.
September 8, 2026 at 9:29 PM
devlead.se
.NET 11 RC 1 was just released🎉, and it's got a go-live license; let's ship some prod workloads, analyze, and learn for the RTM release in November🚀#dotnet

dotnet.microsoft.com/en-us/downlo...
Go-live releases are supported by Microsoft in production. These are typically our release candidate builds, just before the generally available (GA) release.
September 8, 2026 at 9:29 PM
Reposted by Mattias Karlsson
oredev.org
Want to showcase your startup to the Øredev community? Apply to be part of our Emerging Tech Program! Three winners will claim a spot for their solution on our exhibition floor, and take part in an Emerging tech panel on stage.
👉 Apply today! https://forms.gle/7DbXsWL2x2ruugdN9
Young man in a blue vest explaining tech details on a touchscreen at an Emerging Tech Program booth.
September 8, 2026 at 8:37 AM
Reposted by Mattias Karlsson
rangemarten.bsky.social
I had a talk about shaders on #JavaZone. Guaranteed to not help you in your career or at work: vimeo.com/1223743974
Shader Sorcery Summon Surreal Scenery - Mårten Rånge
This is "Shader Sorcery Summon Surreal Scenery - Mårten Rånge" by JavaZone on Vimeo, the home for high quality videos and the people who love them.
vimeo.com
September 7, 2026 at 11:37 AM
devlead.se
Sometimes you need to ship on a Friday, and it's good that you did😎
Error analytics graph going down to zero
September 4, 2026 at 2:13 PM
devlead.se
Localized application exceptions are fun... as one often codes in English, they might not even make sense to a developer who knows the language thrown🤷
September 4, 2026 at 12:18 PM
Reposted by Mattias Karlsson
theverge.com
1Password faced immediate backlash from customers this week over a $300,000 pledge in support of a Linux distro created by David Heinemeier Hansson, who has regularly published overtly racist blog posts that include comments calling for deportation of ethnic minorities in Europe.
1Password wades into a right-wing mess after funding a Linux project
The controversy surrounds David Heinemeier Hansson, who has posted strident anti-vax and anti-immigrant views.
www.theverge.com
September 2, 2026 at 8:20 PM
devlead.se
That's cool👀
awakecoding.com Marc-André Moreau @awakecoding.com · 15d
Here's Windows Terminal in C# and Avalonia instead of C++ and WinUI. Next steps would be Ghostty and cross-platform support 👇
September 2, 2026 at 8:25 PM
Reposted by Mattias Karlsson
avaloniaui.net
Hot Reload for Avalonia is here 🔥

Edit your XAML or C#, and see the changes immediately in your running app. No restart. No renavigation.

Support for Windows, macOS, Linux, iOS and Android.

avaloniaui.net/blog/hot-re...
Hot Reload for Avalonia - Avalonia UI Blog
Avalonia Hot Reload is here: edit XAML and C#, see it live, no restart, on desktop and mobile.
avaloniaui.net
September 2, 2026 at 9:03 AM
Reposted by Mattias Karlsson
whataweekhuh.bsky.social
Captain Haddock looking very frazzled, saying, “What a week, huh?” Tintin leans into the frame and says, “Captain, it’s Wednesday.” Snowy aka Milou is very excited about the drink he has found. Viñeta de Tintin El capitán Haddock, sentado a una mesa y con aspecto de estar agotado, dice: "¡Menuda semana, ¿eh?". Tintín, a su derecha, le dice: "Capitán, es miércoles". A la izquierda, Milú mira muy contento la bebida que está en la mesa.
September 2, 2026 at 10:35 AM
Reposted by Mattias Karlsson
andrewlock.bsky.social
Blogged: The pain of serializing unions and closed class hierarchies with System.Text.Json in .NET 11

andrewlock.net/exploring-th...

In this post I discuss the System.Text.Json support for unions and closed hierarchies coming in .NET 11, the decisions made and some of the sharp edges I hit #dotnet
The pain of serializing unions and closed class hierarchies with System.Text.Json: Exploring the .NET 11 preview - Part 7
In this post I discuss the System.Text.Json support for unions and closed hierarchies coming in .NET 11, the decisions made, and some of the sharp edges I hit
andrewlock.net
September 1, 2026 at 4:13 PM
Reposted by Mattias Karlsson
whataweekhuh.bsky.social
Captain Haddock looking very frazzled, saying, “What a week, huh?” Tintin leans into the frame and says, “Captain, it’s Wednesday.” Snowy aka Milou is very excited about the drink he has found. Viñeta de Tintin El capitán Haddock, sentado a una mesa y con aspecto de estar agotado, dice: "¡Menuda semana, ¿eh?". Tintín, a su derecha, le dice: "Capitán, es miércoles". A la izquierda, Milú mira muy contento la bebida que está en la mesa.
August 26, 2026 at 9:55 AM
Reposted by Mattias Karlsson
kirillosenkov.com
ILSpy working in a browser:

osenkov.com/ilspy

Powered by @ilspy.bsky.social and @avaloniaui.net
Screenshot of a browser tab and ILSpy UI in it: tree with ICSharpCode.Decompiler assembly on the left, with namespaces and types, decompiled assembly attributes in a yellow text editor on the right
August 26, 2026 at 1:25 AM