In 1911, EInstein thought that photons had mass. Still in use 123 years after,

This is an extract from the 1911 paper:
On the Inuence of Gravitation on the Propagation of Light
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2. On the Gravitation of Energy
......
(1a) E₁ = E₂ + E₂/c² Φ
This equation expresses the energy law for the process under
observation. The energy
E₁ arriving at S₁ is greater than the energy E₂, measured by the same
means, which
was emitted from S₂, the excess being the potential energy of the mass
E₂/c² in the
gravitational field.
This shows that in order to satisfy the energy principle we have to
ascribe to the
energy E, before its emission from S₂, a potential energy, due to
gravity, which
corresponds to the (gravitational) mass E₂/c².
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NOTE:  Φ = -GM/r, the gravitational potential on Earth, at a distance r
from its center.
Einstein simplified Eq. 1a for low heights as:
(1) E₁ = E₂ (1 + hγ/c²), where γ is the ground level gravitational
acceleration (today known as g).
As per Planck, it's known that the electromagnetic energies involved
are:
E₁ = hf₁
E₂ = hf₂
Then Eq.1 becomes
f₁ = f₂ (1 + hγ/c²)
OR
Δf/f₂ = hγ/c²
Which is the same equation used in the 1961 Pound-Rebka experiment, the
1971 Hafele-Keating experiment and MANY MORE, like in the 2017 Mudrak
theoretical paper for calculations of the GR effect on Galileo GNSS.
Almost ALL relativists forget that the 1961 paper had the name: "Do
photons have weight?".
All relativists claim that the 1911 paper WAS WRONG, and that was valid
was the 1915 Schwarzschild solution, which is WIDELY USED TODAY, but
that contain the conjugate effects of SR and GR.
But RELATIVISTS FORGET that Schwarzschild solution is theoretically
separated in two parts: GR and SR effects.
Also (Paul and so many others), they FORGET that IT'S IMPOSSIBLE to
measure each effect separately.
So, the 1911 Einstein's equation is ALIVE TODAY, and widely used (with
minor aggregations like quadrupolar momentum J2, which is irrelevant and
can be dismissed here).
What PERSISTS is that Einstein, Pound-Rebka and many others before and
after, ACCEPTED THAT PHOTONS HAD MASS.
If photons have mass (electromagnetic mass), then MANY THEORETICAL
EXPLANATIONS HAVE TO BE REFORMULATED.
If photons have mass, such mass has to be incorporated in the
calculations of gravitational fields and electromagnetic energies, as
Einstein CLAIMED in 1911.
Then, photons falling into Earth's surface GAIN KINETIC ENERGY WHILE
FALLING (blue-shifting), and photons abandoning Earth's surface LOSS
KINETIC ENERGY WHILE ESCAPING (red-shifting).
And the equation that prevails all over of the above is hf = mc². It
also implies that INERTIAL electromagnetic mass IS DIFFERENT FROM
GRAVITATIONAL ELECTROMAGNETIC MASS, and that the first one is variable
with height, in this way:
Δm/m₂ = -hGM/rc²  (h represents the height above surface, being h << r.
Low altitudes).
Deal with that, relativists.