So with the Sting no longer being an Attack, you don't need to use your Action and don't need Investment of the Chain Master to have your Chain Familiar Pseudodragon poison a target. I don't know if that makes it worth picking it over an Imp (Invisibility, Shapechange, more HP, resistances, ...) but it's certainly nice.

Now we can have a Familiar which can deal damage. Exciting.

Not true. Although it doesn't have an attack roll, it's still an attack. It's still a stinger. It's not some innate ability or spell, it literally shanks you with its tail. 

Not true. Although it doesn't have an attack roll, it's still an attack. It's still a stinger. It's not some innate ability or spell, it literally shanks you with its tail. 

Interesting thing I've noticed: They lost their limited telepathy between editions, as well as their keen senses.

This new edition uses Keywords with very explicit and well defined meanings. 

Attacks require attackers to make a d20 vs the targets AC. 

Abilities require the targets to make an ability save.

"Attack Notation. The entry for a monster’s attack starts by identifying whether the attack is a melee or a ranged attack and then provides the attack roll’s bonus, its reach or range, and what happens on a hit. An attack is against one target unless its entry says otherwise."

Pseudodragon can bite. Bite is a melee attack because the stat identifies it as an attack. 

The sting ability states that when the pseudodragon is within 5 ft it can force a creature that it sees to make a con save. No attack roll, just an ability save. 

That they're both listed under actions might be confusing you. 

The IMP statblock might be helpful to illustrate how attacks and abilities are both listed under actions.

Huh, you're right. DC12 is not very much, though, so I would still take investment of the chain master to go with it so the DC becomes your spell casting DC. Still though, a pseudodragon familiar can totally sting someone on their turn. That still means no double/triple sting since the quick attack and attack-with-its-reaction options prevent the sting being selected, only attacks. 

I think they actually nerfed it by making it an ability rather than an attack. Well, at least a casual pact of the chain warlock can have it sting on its turn in addition to their other options.

i'd definitely pick a quasit over this guy

Changes between the 2014 Pseudodragon and the 2024 Pseudodragon:

Armor Class: 13 (Natural Armor) → 14.
Hit Points: 7 (2d4 + 2) → 10 (3d4 + 3)
Skills: Perception +3 [Wisdom +1 + Proficiency +2] → Perception +5 [Wisdom +1 + Expertise +4]
Senses: Passive Perception 13 [18 due to +5 due to Advantage from Keen Senses] → Passive Perception 15.
Keen Senses: removed.
Limited Telepathy: removed.
Multiattack: added.
Bite: No longer a Weapon Attack.
Sting: DC 11 [8 + PB + Con/Wis] → DC 12 [8 + PB + Dex], Damage on fail 4 (1d4+2) Piercing → 5 (2d4) Poison, No longer an attack roll.

() = Officially detailed dice.
[] = Unofficial explanation of modifier values.

Thoughts:

The 2024 Pseudodragon is now marginally better in combat with higher sturdiness, and offense shifted towards its bite attack(s) while the Sting is more consistent with larger spikes in damage albeit the damage is more likely to be resisted or immuned. This is in exchange for a on-the-face-of-it bigger downscale in its overall utility with a worse overall Passive Perception and communication.

As a Warlock's Familiar, while at first glance it would appear that it's an overall worse option for combat than the other alternatives due to having its niche shifted from being a potent anti-hide spotter, to a less potent damage dealer compare to the competition, this is not entirely the case. While its effective Passive Perception is down from 18 to 15, its Blindsight can detect hiding creature due to Hiding Creatures gaining the Invisible Condition. This means a Pseudodragon's niche has mainly shifted playstyle from a passive observer to an active finder by using its Fly Speed to scout around the map + it's action to Dash or Disengage to cover more ground depending on situation. Also of note is that 15 is still high enough to qualify for the same tier of Xanathar's "Waking Someone" rules which is effectively unchanged.

I think that is a more fun rebalance although I am uncertain if the overall effectiveness is higher, lower, or about the same. I wouldn't use it's bite attack unless I knew that the average damage would make the difference in taking the target out which will rarely be the case in higher tiers of play.

Where is telephaty?! :O 

The Amazon Prime delivered cheap remote controlled drone recon drone for free every 1 hour is finally gone.
Looks like you need Beast Bond spell slots expended now if you still want telepathy.
Something I would call way more consistent and balanced as a DM in terms of previously game breaking OP.

I think you'll still get the telepathy since it's mentioned in the find familiar spell from your warlock spell list. But unsure tbh. 

We will see. The game is very loose on terms, this isn't 4E. They may differentiate between attack and attack action for example, with a general concept of offensive action being an attack. 

It can't talk 😭 

There's actually more issue here with Pact of the Chain with Investiture. That says you can use a BA to allow an Attack Action. The PC block for attack action specifies multiple attacks differently, whereas this deals 1d4+2 twice with multiattack. So - sense would dictate that Multiattack is an Attack Action, but it's not specifically defined that way in the rules. It's easy to interpret it also as getting only a single Bite attack.

Likewise, it's common sense to me to consider Sting as an Attack Action, but not by specific definition of what an Attack is. If I had to guess, the RAI is that anything that harms an enemy is balanced behind the Warlock's own action economy. I wish this was all codified better to prevent confusion.

@avoidperil At least the first issue is cleared up in the new MM: Multiattack. I.E., a Warlock's Bonus Action lets a Pseudodragon Multiattack (on its turn?).

Though, it does seem that Sting wouldn't be considered an attack or usable with/as part of an Attack Action as defined above that or in this stat block. I think the MM is consistent with the PHB in that an attack roll constitutes something being an attack. If this is the case, then the wording of Find Familiar even lets it take the Sting action 'as normal' without the Warlock's action economy (or needing Investment, for that matter). Which is to say, the Pseudodragon is the only Find Familiar option a Chain Warlock has that has a repeatable combat-effective option without using their own action economy.

This is all assuming that 'can't attack' means 'can't make an attack roll as part of its action'.

That is an interesting loophole! Indeed, "Bite" says it's an attack, and "Sting" is just listed as a saving throw... noice!

With no more limited telepathy, how are they meant to communicate besides basic gestures?

I wish they would bring back the AD&D "camouflage" ability they had. Of course in AD&D it was some weird mechanic - probably rolling a d6 or percentage, but in 5e we could just give them advantage on stealth checks. 

im choosing this for pact of chain familar