For me it was late 2018 with Qubes 4.0 on refurbished x230. From mailing lists discussions learned x230 “reasonably secure” with Heads. By time saw proposal: second qubes-certified laptop is Lenovo Thinkpad x220/x230 · Issue #1771 · QubesOS/qubes-issues · GitHub had buy i7 x230, 16GB ram, Atheros wifi card, and SSD. Qubes-Community Coreboot on Lenovo X230 guide by one7two99 ton of help to know buy Raspberry Pi 3, Pomona 5250 8-Pin Flash Clip, short Jumper Cables and learn howto external flash. Heads flash was terror 1st time but super reward. Love Qubes OS and use daily. Often confused, still learning lots, but much enjoy! 