Frontier lab releases, open-source checkpoints, multimodal systems, inference stacks, and model capability shifts.
March 2026 frontier tier: GPT‑5.4 Thinking, GPT‑5.4 Pro, and Grok 4.20 (DigitalApplied developer guide)
OpenA March 10–16, 2026 release wave introduced **GPT‑5.4 Standard and Thinking**, **GPT‑5.4 Pro**, and **Grok 4.20**, targeting the top of reasoning and factual accuracy benchmarks across multi‑step problems and agentic task planning.[6] Grok 4.20 is reported with a 2M‑token context window and leading performance on hallucination evaluations, while GPT‑5.4 Thinking adds internal chain‑of‑thought reasoning for complex tasks at higher latency and cost.[6]
OpenAI’s open‑weight gpt‑oss‑120b and gpt‑oss‑20b expand serious open source options (CNBC report)
OpenOpenAI released two **open‑weight** text‑only language models, gpt‑oss‑120b and gpt‑oss‑20b, under Apache 2.0, positioned as lower‑cost, accessible alternatives to proprietary frontier models for developers and businesses.[5] OpenAI reports safety filtering for CBRN‑related data, misuse simulations, and external expert review; both models support sophisticated reasoning, tool use, and chain‑of‑thought processing and are designed to run from consumer hardware to cloud deployments.[5]
Perplexity Pro Search stack: Sonar (Llama 3.1 70B), GPT‑5.2, Claude Sonnet 4.6, Gemini 3.1 Pro, Nemotron 3 Super 120B
OpenPerplexity’s Pro Search layer documents a **multi‑model inference stack** that includes Sonar (powered by Llama 3.1 70B), OpenAI’s **GPT‑5.2**, Anthropic’s **Claude Sonnet 4.6**, Google’s **Gemini 3.1 Pro**, and NVIDIA’s **Nemotron 3 Super 120B**, each optimized for different combinations of reasoning, coding, and multimodal understanding.[2] These models expose explicit “reasoning” toggles or defaults for deeper logical processing, with Sonnet 4.6 highlighted for efficient coding and Gemini 3.1