Subcontracting design and development

Just one more thing, with the 2015 version is it still necessary to have a quality manual?'

Answer
ISO 9001:2015 does not require a quality manual and does not forbid its use. I understand that your question is about an organization subcontracting design and development activities. An organization should evidence planning and control of subcontracted activities. You don’t have to detail your external service provider's design and development, you have to detail supplying or controlling design and development inputs, and at least control activities (at least verification and validation activities).

The following material will provide you information about quality manuals and design and development:
- Article – The future of the Quality Manual in ISO 9001:2015 - https://advisera.com/9001academy/knowledgebase/the-future-of-the-quality-manual-in-iso-90012015/ -manual-in-iso-90012015/
- How to control outsourced processes using ISO 9001 - https://advisera.com/9001academy/blog/2015/05/05/how-to-control-outsourced-processes-using-iso-9001/
- ISO 9001:2015 Internal Auditor Course - https://advisera.com/training/iso-9001-internal-auditor-course/
- Book - Discover ISO 9001:2015 Through Practical Examples - https://advisera.com/books/discover-iso-9001-2015-through-practical-examples/