diff --git a/Cargo.toml b/Cargo.toml
index c0423ae..d54d8c4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,11 +13,12 @@ include = ["src/**/*", "README.md", "CHANGELOG.md"]
 
 [features]
 default = ["compat-3-0-0", "rustls"]
-compat-3-0-0 = ["mongodb/compat-3-0-0"]
-compat-3-3-0 = ["mongodb/compat-3-3-0"]
+compat-3-0-0 = ["mongodb/compat-3-0-0", "bson2"]
+compat-3-3-0 = ["mongodb/compat-3-3-0", "bson3"]
 bson-3 = ["mongodb/bson-3"]
 openssl = ["mongodb/openssl-tls"]
 rustls = ["mongodb/rustls-tls"]
+chrono = ["bson2?/chrono-0_4", "bson3?/chrono-0_4"]
 
 [dependencies]
 mongodb = { version = "3", default-features = false, features = ["dns-resolver"] }
@@ -25,6 +26,8 @@ serde = { version = "1", features = ["derive"] }
 futures-core = "0.3"
 futures-util = "0.3"
 async-trait = "0.1"
+bson2 = { package = "bson", version = "2", optional = true }
+bson3 = { package = "bson", version = "3", optional = true }
 
 [dev-dependencies]
 tokio = "1"