Exient.com has yet to write on their Stories blog about the latest Lemmings feature update, but The Ruins Update - version 8.00 - has been out for a while, & brings neat new features to the game:
Ancient Stairs & Ancient Bridges are essentially indestructible variants of the Lemming-built structures, but what's really cool about them is that they generate as part of a level's layout! I presume they came in response to a common request for "diagonal blocks" to keep the game's geometry interesting. This certainly works!
Energy Blocks, much like Gold Blocks, provide the player a good boost when dug up - Energy! You'll only find them in the latest Planets' levels, so nothing to see here if you're still in the early- or mid-game.
Previewing a level is now possible using a new button in the Instruction/Booster select screen, so you can take in the parts of a puzzle you'll have to deal with & solve them at your pace. No more quick guesswork or taking screenshots to save the Lemmings.
Plus, of course, the newest Seasons & Planets will only be available if you update, given they inevitably make use of the new blocks, so what have you got to lose?