FLAN-UL2
Similar to FLAN-T5, FLAN-UL2 is a model based on Google's popular T5 architecture with an upgraded pre-training procedure dubbed UL2. On most NLU benchmarks, FLAN-UL2 outperforms FLAN-T5 by a significant margin.
A side-by-side comparison of release history, capabilities, licensing and model sizes.
| Attribute |
 FLAN-UL2
|
 Llama
|
|---|---|---|
| Developer | Meta | |
| Current generation | – | Llama 4 |
| Initial release | 2023-03-03 | 2023-02-24 |
| Instruct tuned | Yes | Yes |
| Coding | No | Yes |
| Finetuning | Yes | Yes |
| Open source | Yes | Yes |
| License | Apache 2.0 | Llama Community License |
| Model sizes | 20B | 109B (17B active), 400B (17B active) |
| Links |
Similar to FLAN-T5, FLAN-UL2 is a model based on Google's popular T5 architecture with an upgraded pre-training procedure dubbed UL2. On most NLU benchmarks, FLAN-UL2 outperforms FLAN-T5 by a significant margin.
Llama is Meta's open-weight model family. Llama 4 was its last major generation; Meta's active assistant-model development has shifted to Muse.
Meta introduced LLaMA in February 2023, helping catalyze the modern open-weight model ecosystem. Llama 2 added commercial use and chat tuning, while the Llama 3 series improved scale, multilingual support, and instruction following. Llama 4, released in April 2025, introduced native multimodality and a mixture-of-experts architecture. Meta subsequently shifted its actively promoted assistant-model line to the proprietary Muse family, but Llama models remain widely used and deployed.