As per the listings on the official Oppo website, Neo 5 (2015) and Neo 5s are minor upgrades over the Neo 5 (2014). The two models come with 4.5-inch FWVGA IPS display, Android 4.4-based Color OS 2.0.1, 1GB of RAM, 8GB of internal memory, and microSD card slot. The phones also feature 8MP rear camera, 2MP front shooter, 2000 mAh battery, and dual-SIM support.
Among other specifications, the Neo 5 (2015) is powered by 1.3GHz quad-core MediaTek MT6582 processor, however the Neo 5s packs Qualcomm Snapdragon 410 quad-core SoC. Also, the latter includes 4G LTE support, which is not present in Neo 5 (2015).
There is no word on the availability or pricing of either smartphone right now, but we hope to see an announcement soon.
