[4-Week Course] <Claude Code> Complete Reading Challenge: Finish the Claude Code book by reading 1 hour daily for 4 weeks!
Daily 1 hour, solid development routine in 4 weeks! An intensive curriculum for developers who want to 'properly' master Claude Code. Monday through Friday, move your hands with practical missions, and expand your perspective with reading materials on weekends. From installation to MCP integration, follow along step by step and you'll be able to complete projects with Claude Code before you know it. A 4-week completion-type learning challenge that catches two rabbits at once: fundamentals and practical skills! Meet it now.
[Claude_Code] The Impact of Version Changes and Model Changes
Hello!
Greetings for the first time. (In other words, the author said it's okay to send this instead of Gilbut 😅 )
If you've been paying close attention to the screen while doing Claude code practice recently? Or if you've been watching the news
1) Version changes in Claude code, 2) Changes in the model used by Claude code - you probably noticed these!
[Figure 1] https://github.com/sysnet4admin/_Book_Claude-Code README.md is managed by Claude Code
I wanted to let everyone know about these changes in case there's anything you need to be aware of regarding whether they might affect the hands-on practice, as I thought it would be helpful for your learning!
To put it simply, it does not affect the practice itself!
(It's not 100%, but as you know, AI operates on statistical results, so there's a possibility it might vary slightly.)
So I've summarized below what parts have changed and what these changes mean, so when you have time, if you take a look at the content below, you should be able to read the direction things are heading and quickly check what's changing as well!
If there are any aspects that could affect your progress during the learning period, I will contact you again through a general announcement 😀
1. Updated to Claude Code 2.x
In fact, there were many updates in the 1.x version as well, so when you look at the release notes, you might think, "Is this really enough of a change to justify a major version jump?"
However, there's something you can immediately feel when you actually use it. The response speed has noticeably improved. Beyond simple convenience improvements, speed is crucial for productivity given the nature of agent coding, which involves running countless loops of code generation, testing, and modification.
Another noteworthy feature is checkpointing. At first, I wondered what was different from the existing conversation context switching that was executed with ESC + ESC, but now Claude can save/revert file-level changes it directly modified like snapshots, providing an interface experience similar to an IDE's Undo (Ctrl+Z). Thanks to this, you can create/modify files with Claude code and, when needed, cancel or try new approaches more easily than before.
2. Sonnet 4.5 Release
One of the biggest features of the announced Sonnet 4.5 is its long-term code generation performance capability. Now it can maintain coding workflows for up to dozens of hours. We can expect various synergies that emerge when combined with recently introduced features such as background tasks, subagents, and hooks.
3. AI Market Changes
In the current situation where OpenAI's Codex is gaining attention again, Anthropic's introduction of new features alongside a major version jump can be interpreted not just as a simple feature improvement, but also as a market message and competitive response. On the other hand, it also seems like a result of the fierce competition in the AI market. Since this is a market and industry that changes day by day, I think it's necessary to pay attention to areas beyond just books. In relation to this, I also left the following in the Yes24 developer interview for October 2025, so if you're curious, it might be worth taking a look. (There isn't much other content though 😅 )
[Figure 2] Part of a developer interview on yes24 in October 2025
Thank you.
Jo Hoon, Jung Chan Hoon
