The Simple Machines Forum 2.0 system requirements are as follows:
PHP 4.1.0 or higher
The following must be changed in the php.ini file.
The engine directive must be set to On.
The magic_quotes_sybase directive must be set to Off.
The session.save_path directive must be set to a valid directory or empty.
The file_uploads directive must be set to On.
The upload_tmp_dir directive must be set to a valid directory or empty.
One of the following databases must be installed.
MySQL 4.0.18 or higher (at least 4.1.0 would be better) and PHP MySQL client API version 4.0.18 or higher.
PostgreSQL 8.0 or higher.
SQLite 1.x – 2.x.
The following are required of the database.
There must be at least 2 MB of storage space in the database, although more is highly recommended.
The database user must have at least the following privileges: SELECT, INSERT, UPDATE, DELETE, ALTER, and INDEX.
The database user must have the CREATE and DROP privileges during installation, conversion and some package installs.
About 20 MB of storage space on the web server will be required
Windows, Linux or another Unix based operating system.
GNU Aspell 0.50 or higher (with appropriate dictionaries) for spell checking functionality.
Apache 2.0.x or above with AcceptPathInfo set to On for queryless URL support.
PHP 5.2.0 or higher, with the following set in your php.ini file:
max_input_time set to a value of at least 30.
post_max_size and upload_max_filesize set to the size of the largest attachments you wish to be able to upload.
memory_limit set to at least 8M.
max_execution_time set to at least 15.
register_globals set to Off.
session.use_trans_sid set to Off.
safe mode disabled, or PHP suExec enabled.
MySQL 5.0 or higher and PHP MySQL client API version 5.0 or higher if using MySQL.
PostgreSQL 8.3.3 or higher if using PostgreSQL.
SQLite 2.8 if using SQLite.
GD Graphics Library 2.0 or higher.