In your field, what do you think will still be in use and what will be either deprecated or just entirely out of favor by that point.
Html, css, svg.
Tcp/ip & Ipv6, ipv4 for wifi
K8, c++, java, postgres (as legacy tech)
20 years requires a lot of guessing about communities, libraries, where our society is after a decade of bad ai, mars & moon base. Is Linus still alive? What was his hat trick (3rd act) after linux & git?
Blender probably is big, but also mostly ai driven by then
The simplicity of text is very appealing to developers. But arguably, it's modern IDEs that make dealing with plain text tolerable - without them, the simplicity of text would rapidly lose its shine.
Flint & Steel
Trapping
Boiling water
Foraging
Fishing
Smoke signals
Drums
etc.
Maybe I'm just in a pessimistic mood right now, but the future isn't looking terribly bright to me right this minute.
Things like HTTP, JavaScript, C, C++, Python, Java are all still in regular use now, and will likely still be used 20 years from now.
Virus scanners, firewalls, "trusted boot", and all the government regulation that results from the security holes generated above.
I'm not sure if unlicensed general purpose computing will be available to the working class, or if we will have lost that war in 20 years.
I'm also curious to see when will we fully explore the programming language space. I think the possible ways to write code are finite.
2. WiFi. Sure it will evolve, but it will still be with us, and still work. And security will still be nearly nonexistent. It's the gold standard of wireless interoperability. High speed wireless could move to LiFi, but that's a real stretch given progress to date...
3. Ethernet. If WiFi is the gold standard of wireless interoperability, Ethernet is the gold standard for interoperability, period, and it's also got decades of holding its own and adapting to new needs and challenges. It holds the modern world together, and it'll hold the future together in 20 years, too. I hope Power-Over-Ethernet is a big part of that going forward (N.B. PoE is the first global power standard for non-trivial loads!), but the safety requirements for 1500V isolation have made PoE power hardware too expensive for mass market penetration so far...
4. LTE. Much of what is called 5G today is really just subsequent generations of LTE. It will be with us in 20 years, though it may be getting long in the tooth. I can't see a good replacement for long-ish range connectivity in the near future. (5G mmWave is stupid and barely makes sense even in dense urban areas, outdoors - it's all hat, no cattle.) Satellite wireless may be making inroads in 20 years. (Non-traditional (non-EM) curl-based radios may also start to show up in 20 years, but won't displace RF for most things.)
5. TCP/IP. This is a given. Many endpoints will remain on v4, due to v6's terminally broken and incomprehensible address model, but half will be on v6. (Heck, even I have to look up how to properly write v6 addrs, and I built a Fortune 10 company's IP network and network management systems!) It will continue to evolve, but interoperability is king, and IP delivers. Practicality and real-world usefulness trumps elegance every time. There are good reasons no one uses OSI networking anymore - TCP/IP kicked its ass. Sadly, TCP/IP will have been totally screwed up by the security people in 20 years, and will need replacing before another decade is out...
6. I'm going to go out on a limb and say BSD. Again, it's not only a proven survivor, but it's also architecturally superior to Linux, and has avoided adding the bloat that will soon make Linux (both kernel and distros) unmaintainable - that will happen within 5 years and the fallout will drive many people to switch from Linux to BSD by the time 20 years rolls around. Linux is too important as the world's server OS to go away, but it's whole lot easier to migrate a bunch of that server work to BSD than to move to a non Unix-based OS, and BSD is for all practical purposes, the only OSS option to Linux.
7. Visual Low/No Code environments. Out on another limb. I know this is controversial, and people have been claiming these are coming for decades, but I think AI assist is now to the point that we'll see these start to be really widely used both by developers and many savvy amateurs. Improved visual interfaces and desk-sized touchscreens (8k is about "retina" at that size) will help this happen. Keyboards will still be around, but will be beginning to seen as "quaint"...
8. USB. USB-C may still be around, but USB overall has proven to be nothing if not adaptable, and for all its many faults, USB has survived several decades and still supports most all older devices. It's a survivor.
9. Bluetooth. This wretched pile of steaming crap will never go away. It's not quite bad enough to die or force a replacement: it works just well enough to make everyone think they should use it, but it pretty much never "just works". If it's still around, that will not have changed. Probably the worst technology still in widespread use in 20 years, as it is today. I hope I'm wrong about this, but not hopeful that I am...
10. Unix stream/processor model, shells, and scripting languages. Like cockroaches and sharks, theses have survived eons and will be with us for a loooong time. I see a resurgence of pipe-connected stream/processor apps, perhaps even modified to include things like objects and standard data representations in the pipelines much as PowerShell (one of Microsoft's best ideas, in some ways) does today. Shells and scripting will rule the roost, perhaps through the visual low/no-code environments mentioned above. Awk will still be here, and may still be easier and faster for many types of data massaging than the trendy tools, just like today.
11. Small, low-power computers. The Raspberry Pi has exposed the tip of the iceberg. The little, sub $100 computers have the compute, storage, and RAM of mainframes and supercomputers of only three decades ago, and are no capable of running serious programs to do serious enterprise work. These are even now moving from the hobbyist realm to taking on small and simple, but serious, enterprise server work. Whether ARM, RISC-V, or something else, these lively little mammals will continue to feast on the eggs of the dinosaurs, even the big dinos that live in the cloud today, as the pendulum swings back to distributed localized server computing from the cloud, which itself was preceded by PCs and workstations, minicomputers, and mainframes.
Less certain:
12. Blockchain. (Could be wrong about this one, 50-50 chance...) It will still be around, and still be used as magic pixie dust where it's not needed by people who are either idiots or like controlling/manipulating others. Proof of stake will prevail before proof of work consumes 10% of the energy on the planet. Transactions will still take too long to be practical, and it will still be distressingly possible to have things of value stolen or lost forever. Many people will have lost their ass on NFTs, and deserved it. The blockchain user population will still consist of a surprising number of crooks and scammers.
13. Light-emitting screens. They'll still be around, but will face growing pressure as large colorful,fast, low-power, and foldable/rollable high-res passive (think desk to wall-sized e-paper that looks like a high quality photo) displays take their place.