This mod provides character progressions that will allow all the basic classes to get to lvl 20, where possible I have tried to align progression and spells with 5e rules.

Note that if this mod is added part way through a playthrough some characters may not work correctly as they will have invalid progressions.  Worst case is it will crash the game.  The fix is to drop characters to level 1 using either cheat engine or the respec mod (if working).
This is not a bug with the mod it is just the nature of changing a character that already exists in the game.
Also note that warlocks will lost the ability to cast low level spells as they level up, this is as per 5e rules and not a bug.  The game mechanics prevent me from doing this in a cleaner fashion.
It is also normal to get an error message about not being able to make a story on load, just accept it.


Wizard: lots of new and powerful spells, cone of cold, fireball, power word kill to name a few.  Most spells provided with higher level counterparts.

Warlock: this was very difficult to get to work but is now working well including Mystic Arcanum spells and the Eldritch Master ability that make the warlock much more fun to play as you won't run out of spell half way through every battle and need to rest.

Cleric: lots of new spells here as well with powerful heals and even resurrection.

Ranger: now gets spells and an extra attack.

Fighter: gets lots of extra attacks as per the 5e rules.  Eldritch knight also given some love now with spells to lvl 20.

Rogue: I haven't fully implemented all the rogue bonuses and instead gave them some extra feats.  This is mainly because it is a lot of work and testing.  I would recommend using the mod Rogues Extra which should be after LvlUp in the load order, this adds loads of nice stuff to rogues.

Sorcerer: Patch 6 brought the sorcerer class into the base game so I have added spells and progressions for them to lvl 20.

Druid: Druid progressions and spells are available to lvl 20 but admittedly I haven't been able to really do the class justice.

Barb: Barbarian progressions and spells are available to lvl 20 in a simple format. This is based on the Barbarian progression seen in Weapon Skills Extra


Use:
BG3 Mod Manager, Candor and Vortex compatible.
Install the mod (installation tips below) and level up your characters.  Companions will also be able to level up.
If you are adding this to an existing save it may not work if you are already at max level.
Some icons have been recycled so double check the tooltips but I have tried to avoid using ones that are likely to be duplicated on a class.


Known glitches:
Lvl9 spell slots don't appear in the UI and won't be used by the game, they do exist but the lvl 9 spells will use a lvl 8 slot and be unable to use the lvl 9 slot.  
I added an extra lvl 8 slot to account for this.

When you have a multiple level spell in the spell book it is possible that not all of the levels will appear on the hotbar, just toggle it off and on in the spellbook to get them back.

Tool-tips may disappear when clearing out hot bar, just press escape twice to get them back.

Some text hasn't been entered so there will be the odd bit of error text here and there.

Warlock has a spell slot for each level over 5 - this was required to get the game to allow learning of the Mystic Arcanum spells, I wanted them to have the correct level in the tooltip so needed to do it this way.  
Warlock will end up with lots of spells they can't use, I haven't worked out how to get rid of unused spells yet.  The Warlock mechanic Larian has implemented doesn't work correctly after level 2 spells, I have come up with this system as a compromise.

If used alongside mods that provide extra classes this should cause no problem unless that mod does not include data for them after level 10, in this case attempting to level up to 11 will crash the game.

Leveling up existing mages causes a crash, no problems with new characters though.  If you use cheat engine a workaround is to respec the character before leveling up.  I haven't been able to work out why this happens unfortunately =/

I have only implemented scaling for eldritch blast, all other cantrips will stay at the base game level at this point.  This isn't a bug just an area where I have not developed content.

Installation:
I recommend BG3 mod manager but you can also use candor, vortex or copy the .pak to your mod folder then add the appropriate lines to your modsetting.lsx file (I have included a copy of a working modsettings file as an optional file).
Be sure to make the mod settings file read only afterwards, the game can wipe your mod file otherwise.

The mod folder is normally \Documents\Larian Studios\Baldur's Gate 3\Mods\

The mod settings file is normally in \Documents\Larian Studios\Baldur's Gate 3\PlayerProfiles\Profile Name