It's worth keeping in mind that, in the vast majority of settings, characters don't know about things like classes and levels. So your druid knows you cast a spell* called Eldritch Blast, cool. Do they know that that spell is only available to people who've made pacts with fiends? Doubtful without a solid Arcana check. Wizards, perhaps, have established a technical definition of wizard, and would be keen indeed on knowing how you get by without a spellbook if you're one of them... but no one else would likely notice, and if you call yourself a sorcerer, mage, thaumaturgist, Spirit Tamer, or whatever, few will be in a position to doubt you.

Now if you have an actual imp following you around, there are probably more folks who can recognize that and might object, but it's still far from conclusive - sorcerors and wizards can also have imps as familiars.

_{*KRyan pointed out that technically, in 3.5 this is a spell-like ability, and Spellcraft wouldn't necessarily help you identify it. But it seems that cat's out of the bag, unless your group wants to retcon.}

There are three (and a half) versions

• The classic Ranger as given in the PHB.

• The Ranger with No Spells as given in the Unearthed Arcana: Modifying Classes.

  • This version removes the spellcasting progression from the class and gives them a more nature-based theme. This version has included in it Superiority Dice (from the Fighter's Battle Master archetype) and various abilities that mimic spells, but are explicitly nonmagical.

• The Revised Ranger, which is also in the Unearthed Arcana.

  • This version of the class is what a lot of people enjoy. It upgrades the strength of many of the classic Ranger's abilities. Its Favored Enemy and Natural Explorer abilities are so good, it becomes worth it to consider a 1-level dip in this class just for those abilities.

• In the 2019 Class Feature Variants UA the Ranger (in pdf) was given several alternate, or appending features.

  • The core class is still the one in the PHB, but was given optional features to replace certain features (Natural Explorer, Favored Enemy, etc.), append to options (including a Fighting Style which grants druid cantrips), or add to the spellcasting feature (including adding spells to the class list, spellcasting focus, and the ability to replace spells on long rests).

These three (and half) versions of the Ranger are, in essence, different classes which all just happen to share a name. There are, of course, many archetypes/conclaves, but those minor differences do not constitute a totally different release/version of the Ranger.