The rest of the Republic remains under Level 3 of the Government's plan.
This followed the confirmation that Northern Ireland will be under stricter coronavirus restrictions for four weeks from Friday.
Here we look at how the rules and guidance differ across the island.
Travel
No unnecessary travel should be undertaken outside of your home. However, the regulations do not set limits for the distance that you may travel for any purpose.
You cannot leave your county except for work, education and other essential purposes.
The same restrictions as Level 3, though under Level 4 the advice is that only essential or other designated workers should travel to work.
Household visitors
No mixing of households except in “social bubbles”, which are now limited to a maximum of 10 people from two households. No overnight stays are allowed in another private home unless in a “bubble”.
The Cabinet agreed on Wednesday night that no visitors are permitted into private homes and gardens in all counties in the Republic, except for essential purposes.
In outdoor settings away from home and garden, up to six people from no more than two households can meet while maintaining strict social distancing – including for outdoor exercise and dining.
Organised indoor and outdoor gatherings
Indoor and outdoor gatherings are limited to a maximum of 15 people, except for allowed outdoor sporting events where the relevant number for that will continue to apply. Theatres and conference centres remain closed.
No organised indoor gatherings should take place. Outdoor gatherings of up to 15 people can take place. Museums, galleries and other cultural attractions all closed.
Weddings
Up to 25 guests can attend a wedding or civil partnership ceremony but with no reception.
Up to 25 guests can attend a wedding ceremony and reception.
Up to 6 guests can attend a wedding ceremony and reception.
Religious services
Religious services can take place and places of worship will stay open, but face coverings must be worn when entering and exiting.
Religious services are held online, while places of worship remain open for private prayer.
Funerals
Funerals can take place and are limited to 25 mourners with no pre- or post-funeral gatherings.
Funerals can still take place with a maximum of 25 mourners.
Sports and matches
No indoor sport of any kind or organised contact sport involving household mixing other than at elite level.
Outdoor non-contact training can take place but only in pods of up to 15. Indoors, individual training only. No exercise or dance classes can take place.
There is an exemption for professional and elite sport/inter-county/horse-racing, with these matches and events allowed to take place behind closed doors. However, the exemption which allows for Club Championship games to be played behind closed doors has been removed.
Gyms
Gyms can stay open for individual training only with local enforcement in place.
Gyms, leisure centres and swimming pools can open with protective measures for individual training only.
Gyms, leisure centres and swimming pools are closed.
Pubs and restaurants
Hospitality businesses will close apart from those able to offer deliveries and takeaways for food, with the existing closing time of 11pm remaining.
Bars, cafes, restaurants and wet pubs can stay open for outdoor dining with a maximum of 15 people and takeaways only. No indoor dining. Nightclubs, discos and casinos remain closed.
Hotels and accommodation
There is no specific mention of hotels in the latest guidance. However, it is understood that hotels will be closing for four weeks, according to BBC News NI.
These remain open but services are limited to residents.
These are open only to existing guests and those with “essential non-social and non-tourist purposes”.
Retail and services
The retail sector can stay open, face coverings must be worn. Off licenses and supermarkets cannot sell alcohol after 8pm. However, close-contact services such as hairdressers and beauticians will shut, apart from those relating to essential health interventions and therapeutics.
Retail and services such as hairdressers, beauticians and barbers can remain open with protective measures in place and the use of face coverings.
Essential retail and businesses that are primarily outdoors only can remain open and face coverings must continue to be worn. All other retail and personal services close.
Schools, childcare and universities
Schools and colleges will shut from 19th to 30th October. Universities and further education will deliver remote learning with only essential face-to-face learning where it is absolutely necessary.
Schools and childcare services can remain open with protective measures. Higher and adult education such as universities must escalate protective measures and limit congregation as far as possible.
Schools and creches will remain open with protective measures. Further, higher and adult education moves primarily online with appropriate protective measures in place for essential attendance on site.
Guidance for over-70s and medically vulnerable people
Those at higher risk from infection, including the over 70s, are advised to take particular care and to minimise contact with others.
Those aged over 70 and the medically vulnerable should "exercise judgement" regarding the extent to which they engage with others and in activities outside home, with specific guidance set to be provided.
Nursing home visits
It is recommended that only one person visits a care home at any one time, though care homes in the North may implement their own policy and prohibit visitors or limit visiting times.
Nursing and care home visits are suspended aside from critical and compassionate circumstances.
Public transport
Only for essential journeys and face coverings must be worn.
Face coverings must be worn on public transport. People should only use public transport if they are essential workers or for essential purposes only. People are advised to walk or cycle where possible. Public transport capacity will be restricted to 50 per cent.
As Level 3, though transport will be operating at 25 per cent capacity.
