Does anyone know when will Lightning will become required or mandatory? I recently read that starting in October 2019, what with the release of Winter `20, LEX (Lightning Experience) will be pushed out to orgs on a rolling basis, unless one notifies SFDC Support not to do so.
The new Flow Builder doesn't require Lightning. It's available even if you are using Classic. And while you are correct that becoming proficient in LEX may take more than a few weeks, it's pretty intuitive for both admins and users. I essentially started our transition by enabling LEX and making the pages look very close to the Classic version, with a few notable differences that were quick productivity wins. Phase 2 of our transition is me getting 'fancier' with some of the LEX capabilities, like path, component visibility, rich text components, screen flows, etc.
We've all known Lightning is the future of Salesforce, and this gives you a solid 10 months to prepare for it to be enabled. Test it out as an Admin--you can see how your current org looks in LEX, and you can turn it on and start using it in Sandbox without affecting your users overmuch. Plus, it's just being enabled by default. Salesforce still isn't forcing you to use it exclusively.
If you have any questions about LEX I'd be happy to chat sometime!
