# Deprecated Features

## PHP Core

### Case-Insensitive Constants

The declaration of case-insensitive constants has been deprecated. Passing ENTITY as the third argument to `define` will now generate a deprecation warning. The use of case-insensitive constants with a case that differs from the declaration is also deprecated.

### Namespaced assert()

Declaring a function called `assert()` inside a namespace is deprecated. The `assert` function is subject to special handling by the engine, which may lead to inconsistent behavior when defining a namespaced function with the same name.

### Searching Strings for non-string Needle

Passing a non-string needle to string search functions is deprecated. In the future the needle will be interpreted as a string instead of an ASCII codepoint. Depending on the intended behavior, you should either explicitly cast the needle to string or perform an explicit call to `chr`. The following functions are affected:

- `strpos`

- `strrpos`

- `stripos`

- `strripos`

- `strstr`

- `strchr`

- `strrchr`

- `stristr`

### Strip-Tags Streaming

The `fgetss` function and the [string.strip_tags stream filter](#filters.string) have been deprecated. This also affects the SplFileObject::fgetss method and `gzgetss` function.

## Data Filtering

The explicit usage of the constants `FILTER_FLAG_SCHEME_REQUIRED` and `FILTER_FLAG_HOST_REQUIRED` is now deprecated; both are implied for `FILTER_VALIDATE_URL` anyway.

## Image Processing and GD

`image2wbmp` has been deprecated.

## Internationalization Functions

Usage of the `Normalizer::NONE` form throws a deprecation warning, if PHP is linked with ICU ≥ 56.

## Multibyte String

The following undocumented `mbereg_*()` aliases have been deprecated. Use the corresponding `mb_ereg_*()` variants instead.

- `mbregex_encoding`

- `mbereg`

- `mberegi`

- `mbereg_replace`

- `mberegi_replace`

- `mbsplit`

- `mbereg_match`

- `mbereg_search`

- `mbereg_search_pos`

- `mbereg_search_regs`

- `mbereg_search_init`

- `mbereg_search_getregs`

- `mbereg_search_getpos`

- `mbereg_search_setpos`

## ODBC and DB2 Functions (PDO_ODBC)

The [pdo_odbc.db2_instance_name](#ini.pdo-odbc.db2-instance-name) ini setting has been formally deprecated. It is deprecated in the documentation as of PHP 5.1.1.