diff --git a/Cargo.lock b/Cargo.lock
index 1829427..3a41beb 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -544,7 +544,7 @@ dependencies = [
 
 [[package]]
 name = "py2erg"
-version = "0.0.29"
+version = "0.0.31"
 dependencies = [
  "erg_common",
  "erg_compiler",
@@ -554,7 +554,7 @@ dependencies = [
 
 [[package]]
 name = "pylyzer"
-version = "0.0.29"
+version = "0.0.31"
 dependencies = [
  "els",
  "erg_common",
diff --git a/Cargo.toml b/Cargo.toml
index 67afc36..c2ad452 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -15,7 +15,7 @@ members = [
 ]
 
 [workspace.package]
-version = "0.0.29"
+version = "0.0.31"
 authors = ["Shunsuke Shibayama <sbym1346@gmail.com>"]
 license = "MIT OR Apache-2.0"
 edition = "2021"
@@ -39,6 +39,7 @@ debug = ["erg_compiler/debug", "erg_common/debug", "py2erg/debug"]
 large_thread = ["erg_compiler/large_thread", "erg_common/large_thread", "els/large_thread"]
 pretty = ["erg_compiler/pretty", "erg_common/pretty"]
 backtrace = ["erg_common/backtrace"]
+experimental = ["els/experimental", "erg_compiler/experimental", "erg_common/experimental"]
 
 [dependencies]
 erg_compiler = { workspace = true }
@@ -46,7 +47,7 @@ erg_common = { workspace = true }
 els = { workspace = true }
 rustpython-parser = { workspace = true }
 rustpython-ast = { workspace = true }
-py2erg = { version = "0.0.29", path = "./crates/py2erg" }
+py2erg = { version = "0.0.31", path = "./crates/py2erg" }
 
 [lib]
 path = "src/lib.rs"
diff --git a/README.md b/README.md
index 056f8af..ada29dc 100644
--- a/README.md
+++ b/README.md
@@ -86,6 +86,8 @@ pylyzer converts Python ASTs to Erg ASTs and passes them to Erg's type checker.
 
 * pylyzer (= Erg's type system) has its own type declarations for the Python standard APIs. Typing of all APIs is not complete and may result in an error that such an API does not exist.
 
+* Since pylyzer's type checking is conservative, you may encounter many (possibly false positive) errors. We are working on fixing this, but if you are concerned about editor errors, please turn off the diagnostics feature.
+
 ## TODOs
 
 * [x] type checking