Content Changelog#

All notable changes to learning content (lessons, exercises, assessments) are documented here.

Categories: Added for new content, Changed for updates, Removed for deletions.

Unreleased#

Changed#

  • Merged the Reference section into Learning. The former reference/ section is gone; every topic now lives inside learning/ alongside the tiered tracks:

    • AI cheatsheets under learning/ai/cheatsheets/ (prompt-engineering, llm-api-cheatsheet, embeddings-and-vector-search)

    • AI introduction at learning/ai/introduction and review materials under learning/ai/reviews/

    • Software engineering cheatsheets under learning/software-engineering/cheatsheets/ (git, SQL, API security, testing, containers, architecture, microservices vs serverless)

    • Cloud cheatsheets under learning/cloud-and-infrastructure/cheatsheets/ (AWS core, Kubernetes, CI/CD, ML services)

    • Former 4-file topic format (index/documentation/practice/question) collapsed to single pages with ## Practice and ## Review Questions H2 sections for easier search and bookmarking

  • Three overlap pairs merged into single pages instead of cross-linked duplicates:

    • learning/ai/advanced/evaluation-metrics — RAGAS narrative theory + Python API + practice + review questions

    • learning/cloud-and-infrastructure/advanced/redis-caching — strategies + RAG/LLM caching patterns + practice + review questions

    • learning/cloud-and-infrastructure/advanced/observability — LGTM narrative + PromQL/LogQL patterns + Grafana tips + practice + review questions

  • Translated the Vietnamese frontend practice page to English and moved it to learning/software-engineering/appendix/frontend-practice

  • Sidebar no longer shows a “References” section; the “Learning” entry now contains cheatsheets as siblings of the tiered tracks

  • Added Cloudflare _redirects for all former reference/* URLs so existing bookmarks continue to work

2026-04-10#

Added#

  • 8 new quick-reference topic directories (each with index, documentation, practice, and question files) — all later merged into learning/ during the 2026-04-10 reference-into-learning merge:

    • AI cheatsheets: prompt-engineering, llm-api-cheatsheet, embeddings-and-vector-search; RAGAS API content merged into learning/ai/advanced/evaluation-metrics

    • Cloud & Infrastructure cheatsheets: aws-core-services, kubernetes-quick-reference, ci-cd-patterns; observability cheatsheet content merged into learning/cloud-and-infrastructure/advanced/observability

  • Full teaching content for learning/cloud-and-infrastructure/advanced/observability (three pillars, LGTM stack, RED/USE methods, SLOs and burn-rate alerts)

  • Full teaching content for learning/cloud-and-infrastructure/advanced/redis-caching (strategies, invalidation, stampede mitigation, operational notes)

Changed#

  • Migrated all learning/ai/ content to LangChain 1.x canonical APIs: create_agent from langchain.agents, init_chat_model from langchain.chat_models, messages from langchain.messages (no longer langchain_core.messages), InMemorySaver (was MemorySaver), workflow.add_edge(START, ...) (was set_entry_point)

  • Refreshed model references across AI content to current frontier models: Claude Opus 4.6, Claude Sonnet 4.6, Claude Haiku 4.5, GPT-5.2, Gemini 3 (previously GPT-4, Claude 2/3)

  • Updated training/ai/ assignment prerequisites to Python 3.11+ and LangChain 1.x dependency specs across 18 files; replaced deprecated TavilySearchResults from langchain_community with TavilySearch from langchain-tavily

  • Rewrote llmops-observability.md LangFuse integration from deprecated LLMChain to modern LCEL (prompt | llm); updated LangSmith env vars to canonical LANGSMITH_* names

  • Rewrote applied/tool-calling.md OpenAI section from legacy openai.ChatCompletion.create() v0 SDK (with functions=) to modern client.chat.completions.create() with the unified tools= parameter

  • Refreshed glossary (LLM, Chain, Agent, Context Window entries) to reflect LangChain 1.x and 2026 model landscape

  • Filled missing {doc} refs in training/ai/integration/knowledge/ (added agentic-patterns, graph-rag) and training/cloud-and-infrastructure/applied/knowledge/ (added aws-services)

  • Bumped Python prerequisite from 3.9+/3.10+ to 3.11+ in glossary, training/ai/overview.md, slide-deck, and 18 training assignment files

2026-04-03#

Added#

  • Context Engineering lesson — context window anatomy, token budgeting, write vs. read context, dynamic assembly, caching, grounding patterns

  • Harness Engineering lesson — eval harness architecture, dataset curation, deterministic and LLM-as-judge metrics, regression testing, CI/CD integration

  • Context Engineering training materials: practice assignment and quiz

  • Harness Engineering training materials: practice assignment and quiz

  • Intro paragraphs to 15 lesson pages for better previews and SEO

  • Section descriptions on all Learning, Training, and Resources index pages

Changed#

  • Restructured all three domains into 4-tier progression: foundations → applied → advanced → integration

  • Renamed “Learn” section to “Learning” site-wide

  • Organized Cloud reference guides by functional domain

  • Moved greenlets lesson to foundations, advanced-indexing training to core-techniques

  • Normalized page titles for consistency across all sections

  • Replaced 62 diagram images with Mermaid code blocks across 28 files

  • Resolved all markdownlint issues: added code block languages, image alt text, and heading fixes across 52 files

2026-03-22#

Added#

  • Glossary with 70+ terms across 7 domains

  • Contributor profiles and presentation decks in Resources

Changed#

  • Reorganized all content into Learning / Training / Resources structure (the initial Learn / Training / Reference / Resources split was later consolidated by merging Reference back into Learning)

  • AI lessons moved to Learning > AI (foundations, core techniques, advanced)

  • Software Engineering lessons moved to Learning > Software Engineering

  • Cloud & Infrastructure lessons moved to Learning > Cloud & Infrastructure

  • All quizzes, assignments, and exams moved to Training sections

  • Blog articles converted to quick-lookup cheatsheets (later moved under each domain’s cheatsheets/ subdir)

  • Added SEO meta descriptions to main pages

2026-03-03#

Added#

  • AI Fundamentals training module — knowledge checks, practice assignments, and final exam

  • RAG Optimization training module — hybrid search, query transformation, post-retrieval quizzes and project

  • LLMOps & Evaluation training module — experiment comparison, observability quizzes and project

  • LangGraph & Agentic AI training module — agentic patterns, human-in-the-loop, multi-agent quizzes and project

  • DevOps Essentials training module — containerization quiz, CI/CD assignment, and final exam

  • Cloud Essentials training module — AWS services quiz and final exam

  • Microservices Architecture training module — API gateway, async communication, saga pattern project

2026-02-09#

Added#

  • Advanced indexing techniques lesson (semantic chunking, HNSW)

  • Syllabi for all 7 fresher training modules

  • Quiz and exam materials for AI Fundamentals and AI Advanced tracks

Changed#

  • Updated RAG evaluation metrics documentation with new images

2026-02-03#

Added#

  • AWS cloud services overview

  • Azure ML services overview

  • LLM evaluation and FastAPI monolith lessons

Changed#

  • Expanded Docker documentation with fundamentals, optimization, and multi-stage builds

  • Enhanced Git and Docker Compose docs with security and best practices

  • Improved testing methodologies coverage (white box, black box)

2026-01-26#

Added#

  • Fresher training program structure with 7 modules

  • AI Fundamentals knowledge base (generative AI, RAG theory, modern RAG architecture, LangChain, building RAG agents)

2026-01-17#

Added#

  • Agentic AI roadmap and patterns

  • Git Collaboration Workflow article

  • API security, JWT authentication, and Redis caching articles

  • AI introductory blog post (AI, Generative AI, LLMs, RAG overview)

Changed#

  • Updated Docker and Compose docs with uv and BuildKit best practices

  • Updated CI/CD workflows documentation

  • Updated Git references with Pro Git and GitHub Skills courses

  • Revised observability and experiment comparison content

2026-01-08#

Added#

  • Initial documentation site with blog-style content

  • Software Engineering articles: Git collaboration, database design, API security, caching strategies, testing methodologies, Docker best practices, microservices vs serverless, CI/CD pipelines, and design patterns

  • AI module 1 (RAG foundations) and module 2 (RAG implementation)