While being out-of-combat for 5 seconds, swap one of your equipped summoner spells to a new, single use summoner spell. You cannot select a summoner spell you have already equipped.
Your first swap becomes available at the 6 minute mark, with an initial 240 second cooldown. Selecting a summoner spell reduces the swap cooldown by 20 seconds, up to once per unique summoner spell. You must swap to 3 different summoner spells before returning to one you've already used.
Selecting a summoner spell puts it on a 5 second cooldown.
Using a selected summoner spell puts the summoner spell on the same slot on a 10 second cooldown.
Unique summoner spell cap decreased. Cooldown reduction per summoner spell increased. Overall available cooldown reduction at max summs unchanged.
Unsealed Spellbook is on the weak side since its rework. We're letting players reach max cooldown reduction more quickly (and without having to cycle through as many spells).
UNIQUE SUMMONER CAP :  ⇒ 6
COOLDOWN REDUCTION PER SUMMONER SPELL :  ⇒ 20 seconds
Unsealed Spellbook is now a completely different keystone.
Unsealed Spellbook was intended to offer a keystone option for players who wanted to be able to reactively opt into a different summoner spell to match the current game state. Problem is, the old Unsealed Spellbook required far too much advance planning, and then locked the player into that choice for far too long. In reality, many players took Unsealed Spellbook just for a lower Flash cooldown, not caring a ton about the swapping gameplay except to get Teleport every once in awhile.
The new Unsealed Spellbook can be swapped anywhere—as long as you're out of combat. Once you use the new summoner spell, it's back to your old one. This solves both of the previous problems: requiring too much preparation, and locking you in for too long.
TAKE THIS! Swap one of your equipped summoner spells to a new, single-use summoner spell. After using the single-use summoner spell, your original summoner spell will swap back in.
FIRST SWAP AVAILABLE : 6 minutes
SWAP COOLDOWN : 4 minutes, permanently reduced by 15 seconds each time you swap to a summoner spell you haven't yet swapped to
STILL TICKING : Your original summoner spells continue cooling down in the background while swapped out
STORE COMES TO YOU : You can now swap your summoner spells anywhere on the map as long as you're out of combat
BUGFIX : 3.9 Closing the Unsealed Spellbook tab while dead no longer prevents you from re-opening it until respawn
Summoner spell cooldown reduction decreased.
Unsealed Spellbook is supposed to be the keystone for players who want to swap summoner spells and alter their capabilities mid-game. Turns out that much Summoner Spell cooldown reduction is good even if you never swap all game, so we're reducing the amount Unsealed Spellbook gives.
SUMMONER SPELL COOLDOWN REDUCTION : [25%] ⇒ 15%
KEEP YOUR RECEIPT Gain a Summoner Shard at 2 minutes and another every 6 minutes after (max 2 shards). While near the shop, you can exchange 1 Summoner Shard to replace a Summoner Spell with a different one.
UR A WIZARD Summoner Spell cooldowns are reduced by 25%
CAN'T BUY TALENT Buying Smite won't grant access to Smite items (you'll have to start with Smite)
SUMMONER FRAUD You cannot have two of the same Summoner Spell