The Republic of Ireland government has confirmed (see https://www.gov.ie/en/press-release/42653-government-reaffirms-commitment-to-participate-in-the-unitary-patent-and-unified-patent-court/) that it is committed to participating in the unitary patent and Unified Patent Court system. It was one of the original signatories to the UPC Agreement back in 2013. Since then many other countries have ratified the Agreement - only Germany's deposit of its instrument of ratification is needed to bring the Agreement fully into force. However, Ireland is not one of those countries, meaning that even if the UPC Agreement comes into force in full, the jurisdiction of the new court would not as things stand extend to Ireland.
The Irish government's announcement on 28 June confirms that it will hold a referendum either in 2023 or 2024, which if approved will enable Ireland to ratify the Agreement and participate in the new patent system. Importantly, Ireland also intends to host a local division of the court. This could be very interesting for litigants, as the UPC procedure has been heavily influenced by the common law approach to litigation, and now that the United Kingdom is no longer participating (as a consequence of the UK leaving the EU), the Republic of Ireland will essentially be the only common law jurisdiction participating. An Ireland division could therefore be quite influential in the development of UPC practice.