README.md in argon2-2.2.0 vs README.md in argon2-2.3.0

@@ -25,32 +25,56 @@
 
 ```ruby
 require 'argon2'
 ```
 
-To generate a hash using specific time and memory cost:
+To utilise default costs ([RFC 9106](https://www.rfc-editor.org/rfc/rfc9106#name-parameter-choice)'s lower-memory, second recommended parameters):
 
 ```ruby
-hasher = Argon2::Password.new(t_cost: 2, m_cost: 16, p_cost: 1)
+hasher = Argon2::Password.new
 hasher.create("password")
-    => "$argon2i$v=19$m=65536,t=2,p=1$jL7lLEAjDN+pY2cG1N8D2g$iwj1ueduCvm6B9YVjBSnAHu+6mKzqGmDW745ALR38Uo"
 ```
 
-To utilise default costs:
+Alternatively, use this shortcut:
 
 ```ruby
-hasher = Argon2::Password.new
+Argon2::Password.create("password")
+    => "$argon2i$v=19$m=65536,t=2,p=1$61qkSyYNbUgf3kZH3GtHRw$4CQff9AZ0lWd7uF24RKMzqEiGpzhte1Hp8SO7X8bAew"
+```
+
+If your use case can afford the higher memory consumption/cost, you can/should specify to use RFC 9106's first recommended parameters:
+
+```ruby
+hasher = Argon2::Password.new(profile: :rfc_9106_high_memory)
 hasher.create("password")
+    => "$argon2id$v=19$m=2097152,t=1,p=4$LvHa74Yax7uCWPN7P6/oQQ$V1dMt4dfuYSmLpwUTpKUzg+RrXjWzWHlE6NLowBzsAg"
 ```
 
-Alternatively, use this shortcut:
+To generate a hash using one of the other `Argon::Profiles` names:
 
 ```ruby
-Argon2::Password.create("password")
-    => "$argon2i$v=19$m=65536,t=2,p=1$61qkSyYNbUgf3kZH3GtHRw$4CQff9AZ0lWd7uF24RKMzqEiGpzhte1Hp8SO7X8bAew"
+# Only use this profile in testing env, it's unsafe!
+hasher = Argon2::Password.new(profile: :unsafe_cheapest)
+hasher.create("password")
+    => "$argon2id$v=19$m=8,t=1,p=1$HZZHG3oTqptqgrxWxFic5g$EUokHMU6m6w2AVIEk1MpZBhVwW9Nj+ESRjPwTBVtWpY"
 ```
 
+The list of named cost profiles are:
+
+* `:rfc_9106_high_memory`: the first recommended option but is expensive
+* `:rfc_9106_low_memory`: the second recommended option (default)
+* `:pre_rfc_9106`: the previous default costs for `ruby-argon2` <= v2.2.0, before offering RFC 9106 named profiles
+* `:unsafe_cheapest`: Strictly for testing, the minimum costs allowed by Argon2 for the fastest hashing speed
+
+To generate a hash using specific time and memory cost:
+
+```ruby
+hasher = Argon2::Password.new(t_cost: 2, m_cost: 16, p_cost: 1)
+hasher.create("password")
+    => "$argon2i$v=19$m=65536,t=2,p=1$jL7lLEAjDN+pY2cG1N8D2g$iwj1ueduCvm6B9YVjBSnAHu+6mKzqGmDW745ALR38Uo"
+```
+
 You can then use this function to verify a password against a given hash. Will return either true or false.
 
 ```ruby
 Argon2::Password.verify_password("password", secure_password)
 ```
@@ -78,9 +102,12 @@
 You should also be able to pass Steep checks:
 ```sh
 steep check
 ```
 These tools will need to be installed manually at this time and will be added to Gemfiles after much further testing.
+
+## Version 2.2.0
+This version changed the way the build system works to deal with a new version of Rubygems. See https://github.com/technion/ruby-argon2/issues/56.
 
 ## Version 2.0 - Argon 2id
 Version 2.x upwards will now default to the Argon2id hash format. This is consistent with current recommendations regarding Argon2 usage. It remains capable of verifying existing hashes.
 
 ## Important notes regarding version 1.0 upgrade