Will I need a new updated invitation letter from my host, since the old one is a year old for customs?

To ensure accurate information, it's recommended that you contact the Algerian embassy or consulate in your country for the most up-to-date travel requirements, visa validity, and any specific instructions for entry into Algeria. They will be able to guide you appropriately based on your individual circumstances.

That being said, here are some points to consider:

• Invitation Letter: Typically, an invitation letter for travel purposes does not have a strict expiration date. However, it's advisable to have a recent letter to avoid any potential issues at the customs checkpoint. If your invitation letter is more than a year old, it might be a good idea to request an updated one from your host. This can serve as proof of your purpose of travel and your host's support during your stay.
• Travel Eligibility: As long as you have a valid visa and meet all the entry requirements for Algeria, you should still be able to travel there. However, it's essential to verify the current travel restrictions, visa validity, and any additional requirements or any other factors that may have changed since your last attempt to travel.
• Customs Questions: When you arrive in Algeria, you can expect to go through customs and immigration. The customs officers may ask you questions related to the purpose of your visit, the duration of your stay, where you will be staying, and other standard immigration inquiries. It's important to answer truthfully and provide any necessary documentation to support your answers, such as your invitation letter, hotel reservations, return flight tickets, and proof of sufficient funds to cover your expenses during your stay.