Please let me know if there is a PHP ethereum API or SDK, with the following requirements:
- The project must be currently maintained. Don't send a link to a project that has not been updated in 2 years.
- I don't want to open any additional ports on my Linux server.
- I need to add transactions to the Ropsten Testnet.
- There can't be any limits to requests (such as 200 requests per hour), and there can't be a monthly fee.
- It must be a stable, proven API or SDK that will not be terminated in the near future.