What are the ICAO fuel reserve requirements?
The following includes the changes you allude to (which were proposed in ICAO State Letter SP 59/4.1-11/8 on June 30, 2011).

Commercial Flights

Per ICAO Annex 6, Part I, section 4.3.6 "Fuel Requirements," airplanes should calculate their required fuel quantity as follows (summary; see below for actual ICAO text):


Taxi fuel
Trip fuel (to reach intended destination)
Contingency fuel (higher of 5% of "trip fuel" or 5 minutes of holding flight)
Destination alternate fuel (to fly a missed and reach an alternate)
Final reserve fuel (45 minutes of holding flight for reciprocating engines, 30 minutes for jets)
Additional fuel (if needed to guarantee ability to reach an alternate with an engine failure or at lower altitude due to a pressurization loss)
Discretionary fuel (if the pilot in command wants it)


General Aviation

For general aviation, ICAO Annex 6 Part II, section 2.2.3.6 "Fuel and oil supply" requires:


For IFR, enough fuel to reach destination, then alternate (if required), plus 45 minutes
For day VFR, enough fuel to reach destination plus 30 minutes
For night VFR, enough fuel to reach destination plus 45 minutes


ICAO Annex 6 Part I

From the ninth edition:


  4.3.6.3 The pre-flight calculation of usable fuel required shall include:
  
  a) taxi fuel, which shall be the amount of fuel expected to be consumed before take-off;
  
  b) trip fuel, which shall be the amount of fuel required to enable the aeroplane to fly from take-off, or the point of in-flight
  re-planning, until landing at the destination aerodrome taking into account the operating conditions of 4.3.6.2 b);
  
  c) contingency fuel, which shall be the amount of fuel required to compensate for unforeseen factors. It shall be five per
  cent of the planned trip fuel or of the fuel required from the point of in-flight re-planning based on the consumption
  rate used to plan the trip fuel but, in any case, shall not be lower than the amount required to fly for five minutes at
  holding speed at 450 m (1 500 ft) above the destination aerodrome in standard conditions;
  
  
    Note.— Unforeseen factors are those which could have an influence on the fuel consumption to the destination
    aerodrome, such as deviations of an individual aeroplane from the expected fuel consumption data, deviations from
    forecast meteorological conditions, extended taxi times before take-off, and deviations from planned routings and/or
    cruising levels.
  
  
  d) destination alternate fuel, which shall be:
  
  
  where a destination alternate aerodrome is required, the amount of fuel required to enable the aeroplane to:
  i) perform a missed approach at the destination aerodrome;
  ii) climb to the expected cruising altitude;
  iii) fly the expected routing;
  iv) descend to the point where the expected approach is initiated; and
  v) conduct the approach and landing at the destination alternate aerodrome; or
  where two destination alternate aerodromes are required, the amount of fuel, as calculated in 4.3.6.3 d) 1),
  required to enable the aeroplane to proceed to the destination alternate aerodrome which requires the greater
  amount of alternate fuel; or
  where a flight is operated without a destination alternate aerodrome, the amount of fuel required to enable the
  aeroplane to fly for 15 minutes at holding speed at 450 m (1 500 ft) above destination aerodrome elevation in
  standard conditions; or
  where the aerodrome of intended landing is an isolated aerodrome:
  i) for a reciprocating engine aeroplane, the amount of fuel required to fly for 45 minutes plus 15 per cent of the
  flight time planned to be spent at cruising level, including final reserve fuel, or two hours, whichever is less;
  or
  ii) for a turbine-engined aeroplane, the amount of fuel required to fly for two hours at normal cruise
  consumption above the destination aerodrome, including final reserve fuel;
  
  
  e) final reserve fuel, which shall be the amount of fuel calculated using the estimated mass on arrival at the destination
  alternate aerodrome, or the destination aerodrome when no destination alternate aerodrome is required:
  
  
  for a reciprocating engine aeroplane, the amount of fuel required to fly for 45 minutes, under speed and altitude
  conditions specified by the State of the Operator; or
  for a turbine-engined aeroplane, the amount of fuel required to fly for 30 minutes at holding speed at 450 m
  (1 500 ft) above aerodrome elevation in standard conditions;
  
  
  f) additional fuel, which shall be the supplementary amount of fuel required if the minimum fuel calculated in accordance with 4.3.6.3 b), c), d) and e) is not sufficient to:
  
  
  allow the aeroplane to descend as necessary and proceed to an alternate aerodrome in the event of engine failure
  or loss of pressurization, whichever requires the greater amount of fuel based on the assumption that such a failure
  occurs at the most critical point along the route;
  i) fly for 15 minutes at holding speed at 450 m (1 500 ft) above aerodrome elevation in standard conditions; and
  ii) make an approach and landing;
  allow an aeroplane engaged in EDTO to comply with the EDTO critical fuel scenario as established by the State
  of the Operator;
  meet additional requirements not covered above;
  
  
  
    Note 1.— Fuel planning for a failure that occurs at the most critical point along a route (4.3.6.3 f) 1)) may place
    the aeroplane in a fuel emergency situation based on 4.3.7.2.
    
    Note 2.— Guidance on EDTO critical fuel scenarios is contained in Attachment D;
  
  
  g) discretionary fuel, which shall be the extra amount of fuel to be carried at the discretion of the pilot-in-command.


ICAO Annex 6 Part II


  2.2.3.6 Fuel and oil supply
  
  A flight shall not be commenced unless, taking into account both the meteorological conditions and any delays that are
  expected in flight, the aeroplane carries sufficient fuel and oil to ensure that it can safely complete the flight. The amount of
  fuel to be carried must permit:
  
  a) when the flight is conducted in accordance with the instrument flight rules and a destination alternate aerodrome is
  not required in accordance with 2.2.3.5, flight to the aerodrome of intended landing, and after that, for at least 45
  minutes at normal cruising altitude; or
  
  b) when the flight is conducted in accordance with the instrument flight rules and a destination alternate aerodrome is
  required, flight from the aerodrome of intended landing to an alternate aerodrome, and after that, for at least 45
  minutes at normal cruising altitude; or
  
  c) when the flight is conducted in accordance with the visual flight rules by day, flight to the aerodrome of intended
  landing, and after that, for at least 30 minutes at normal cruising altitude; or
  
  d) when the flight is conducted in accordance with the visual flight rules by night, flight to the aerodrome of intended
  landing and thereafter for at least 45 minutes at normal cruising altitude.